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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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package java.net;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Hashtable;
import java.util.Date;
import java.util.StringTokenizer;
import java.util.Collections;
import java.util.Map;
import java.util.List;
import java.security.Permission;
import java.security.AccessController;
import sun.security.util.SecurityConstants;
import sun.net.www.MessageHeader;

The abstract class URLConnection is the superclass of all classes that represent a communications link between the application and a URL. Instances of this class can be used both to read from and to write to the resource referenced by the URL. In general, creating a connection to a URL is a multistep process:
openConnection() connect()
Manipulate parameters that affect the connection to the remote resource. Interact with the resource; query header fields and contents.
---------------------------->
time
  1. The connection object is created by invoking the openConnection method on a URL.
  2. The setup parameters and general request properties are manipulated.
  3. The actual connection to the remote object is made, using the connect method.
  4. The remote object becomes available. The header fields and the contents of the remote object can be accessed.

The setup parameters are modified using the following methods:

  • setAllowUserInteraction
  • setDoInput
  • setDoOutput
  • setIfModifiedSince
  • setUseCaches

and the general request properties are modified using the method:

  • setRequestProperty

Default values for the AllowUserInteraction and UseCaches parameters can be set using the methods setDefaultAllowUserInteraction and setDefaultUseCaches.

Each of the above set methods has a corresponding get method to retrieve the value of the parameter or general request property. The specific parameters and general request properties that are applicable are protocol specific.

The following methods are used to access the header fields and the contents after the connection is made to the remote object:

  • getContent
  • getHeaderField
  • getInputStream
  • getOutputStream

Certain header fields are accessed frequently. The methods:

  • getContentEncoding
  • getContentLength
  • getContentType
  • getDate
  • getExpiration
  • getLastModifed

provide convenient access to these fields. The getContentType method is used by the getContent method to determine the type of the remote object; subclasses may find it convenient to override the getContentType method.

In the common case, all of the pre-connection parameters and general request properties can be ignored: the pre-connection parameters and request properties default to sensible values. For most clients of this interface, there are only two interesting methods: getInputStream and getContent, which are mirrored in the URL class by convenience methods.

More information on the request properties and header fields of an http connection can be found at:

http://www.ietf.org/rfc/rfc2616.txt
Invoking the close() methods on the InputStream or OutputStream of an URLConnection after a request may free network resources associated with this instance, unless particular protocol specifications specify different behaviours for it.
Author: James Gosling
See Also:
Since: JDK1.0
/** * The abstract class {@code URLConnection} is the superclass * of all classes that represent a communications link between the * application and a URL. Instances of this class can be used both to * read from and to write to the resource referenced by the URL. In * general, creating a connection to a URL is a multistep process: * * <center><table border=2 summary="Describes the process of creating a connection to a URL: openConnection() and connect() over time."> * <tr><th>{@code openConnection()}</th> * <th>{@code connect()}</th></tr> * <tr><td>Manipulate parameters that affect the connection to the remote * resource.</td> * <td>Interact with the resource; query header fields and * contents.</td></tr> * </table> * ----------------------------&gt; * <br>time</center> * * <ol> * <li>The connection object is created by invoking the * {@code openConnection} method on a URL. * <li>The setup parameters and general request properties are manipulated. * <li>The actual connection to the remote object is made, using the * {@code connect} method. * <li>The remote object becomes available. The header fields and the contents * of the remote object can be accessed. * </ol> * <p> * The setup parameters are modified using the following methods: * <ul> * <li>{@code setAllowUserInteraction} * <li>{@code setDoInput} * <li>{@code setDoOutput} * <li>{@code setIfModifiedSince} * <li>{@code setUseCaches} * </ul> * <p> * and the general request properties are modified using the method: * <ul> * <li>{@code setRequestProperty} * </ul> * <p> * Default values for the {@code AllowUserInteraction} and * {@code UseCaches} parameters can be set using the methods * {@code setDefaultAllowUserInteraction} and * {@code setDefaultUseCaches}. * <p> * Each of the above {@code set} methods has a corresponding * {@code get} method to retrieve the value of the parameter or * general request property. The specific parameters and general * request properties that are applicable are protocol specific. * <p> * The following methods are used to access the header fields and * the contents after the connection is made to the remote object: * <ul> * <li>{@code getContent} * <li>{@code getHeaderField} * <li>{@code getInputStream} * <li>{@code getOutputStream} * </ul> * <p> * Certain header fields are accessed frequently. The methods: * <ul> * <li>{@code getContentEncoding} * <li>{@code getContentLength} * <li>{@code getContentType} * <li>{@code getDate} * <li>{@code getExpiration} * <li>{@code getLastModifed} * </ul> * <p> * provide convenient access to these fields. The * {@code getContentType} method is used by the * {@code getContent} method to determine the type of the remote * object; subclasses may find it convenient to override the * {@code getContentType} method. * <p> * In the common case, all of the pre-connection parameters and * general request properties can be ignored: the pre-connection * parameters and request properties default to sensible values. For * most clients of this interface, there are only two interesting * methods: {@code getInputStream} and {@code getContent}, * which are mirrored in the {@code URL} class by convenience methods. * <p> * More information on the request properties and header fields of * an {@code http} connection can be found at: * <blockquote><pre> * <a href="http://www.ietf.org/rfc/rfc2616.txt">http://www.ietf.org/rfc/rfc2616.txt</a> * </pre></blockquote> * * Invoking the {@code close()} methods on the {@code InputStream} or {@code OutputStream} of an * {@code URLConnection} after a request may free network resources associated with this * instance, unless particular protocol specifications specify different behaviours * for it. * * @author James Gosling * @see java.net.URL#openConnection() * @see java.net.URLConnection#connect() * @see java.net.URLConnection#getContent() * @see java.net.URLConnection#getContentEncoding() * @see java.net.URLConnection#getContentLength() * @see java.net.URLConnection#getContentType() * @see java.net.URLConnection#getDate() * @see java.net.URLConnection#getExpiration() * @see java.net.URLConnection#getHeaderField(int) * @see java.net.URLConnection#getHeaderField(java.lang.String) * @see java.net.URLConnection#getInputStream() * @see java.net.URLConnection#getLastModified() * @see java.net.URLConnection#getOutputStream() * @see java.net.URLConnection#setAllowUserInteraction(boolean) * @see java.net.URLConnection#setDefaultUseCaches(boolean) * @see java.net.URLConnection#setDoInput(boolean) * @see java.net.URLConnection#setDoOutput(boolean) * @see java.net.URLConnection#setIfModifiedSince(long) * @see java.net.URLConnection#setRequestProperty(java.lang.String, java.lang.String) * @see java.net.URLConnection#setUseCaches(boolean) * @since JDK1.0 */
public abstract class URLConnection {
The URL represents the remote object on the World Wide Web to which this connection is opened.

The value of this field can be accessed by the getURL method.

The default value of this variable is the value of the URL argument in the URLConnection constructor.

See Also:
/** * The URL represents the remote object on the World Wide Web to * which this connection is opened. * <p> * The value of this field can be accessed by the * {@code getURL} method. * <p> * The default value of this variable is the value of the URL * argument in the {@code URLConnection} constructor. * * @see java.net.URLConnection#getURL() * @see java.net.URLConnection#url */
protected URL url;
This variable is set by the setDoInput method. Its value is returned by the getDoInput method.

A URL connection can be used for input and/or output. Setting the doInput flag to true indicates that the application intends to read data from the URL connection.

The default value of this field is true.

See Also:
/** * This variable is set by the {@code setDoInput} method. Its * value is returned by the {@code getDoInput} method. * <p> * A URL connection can be used for input and/or output. Setting the * {@code doInput} flag to {@code true} indicates that * the application intends to read data from the URL connection. * <p> * The default value of this field is {@code true}. * * @see java.net.URLConnection#getDoInput() * @see java.net.URLConnection#setDoInput(boolean) */
protected boolean doInput = true;
This variable is set by the setDoOutput method. Its value is returned by the getDoOutput method.

A URL connection can be used for input and/or output. Setting the doOutput flag to true indicates that the application intends to write data to the URL connection.

The default value of this field is false.

See Also:
/** * This variable is set by the {@code setDoOutput} method. Its * value is returned by the {@code getDoOutput} method. * <p> * A URL connection can be used for input and/or output. Setting the * {@code doOutput} flag to {@code true} indicates * that the application intends to write data to the URL connection. * <p> * The default value of this field is {@code false}. * * @see java.net.URLConnection#getDoOutput() * @see java.net.URLConnection#setDoOutput(boolean) */
protected boolean doOutput = false; private static boolean defaultAllowUserInteraction = false;
If true, this URL is being examined in a context in which it makes sense to allow user interactions such as popping up an authentication dialog. If false, then no user interaction is allowed.

The value of this field can be set by the setAllowUserInteraction method. Its value is returned by the getAllowUserInteraction method. Its default value is the value of the argument in the last invocation of the setDefaultAllowUserInteraction method.

See Also:
/** * If {@code true}, this {@code URL} is being examined in * a context in which it makes sense to allow user interactions such * as popping up an authentication dialog. If {@code false}, * then no user interaction is allowed. * <p> * The value of this field can be set by the * {@code setAllowUserInteraction} method. * Its value is returned by the * {@code getAllowUserInteraction} method. * Its default value is the value of the argument in the last invocation * of the {@code setDefaultAllowUserInteraction} method. * * @see java.net.URLConnection#getAllowUserInteraction() * @see java.net.URLConnection#setAllowUserInteraction(boolean) * @see java.net.URLConnection#setDefaultAllowUserInteraction(boolean) */
protected boolean allowUserInteraction = defaultAllowUserInteraction; private static boolean defaultUseCaches = true;
If true, the protocol is allowed to use caching whenever it can. If false, the protocol must always try to get a fresh copy of the object.

This field is set by the setUseCaches method. Its value is returned by the getUseCaches method.

Its default value is the value given in the last invocation of the setDefaultUseCaches method.

See Also:
/** * If {@code true}, the protocol is allowed to use caching * whenever it can. If {@code false}, the protocol must always * try to get a fresh copy of the object. * <p> * This field is set by the {@code setUseCaches} method. Its * value is returned by the {@code getUseCaches} method. * <p> * Its default value is the value given in the last invocation of the * {@code setDefaultUseCaches} method. * * @see java.net.URLConnection#setUseCaches(boolean) * @see java.net.URLConnection#getUseCaches() * @see java.net.URLConnection#setDefaultUseCaches(boolean) */
protected boolean useCaches = defaultUseCaches;
Some protocols support skipping the fetching of the object unless the object has been modified more recently than a certain time.

A nonzero value gives a time as the number of milliseconds since January 1, 1970, GMT. The object is fetched only if it has been modified more recently than that time.

This variable is set by the setIfModifiedSince method. Its value is returned by the getIfModifiedSince method.

The default value of this field is 0, indicating that the fetching must always occur.

See Also:
/** * Some protocols support skipping the fetching of the object unless * the object has been modified more recently than a certain time. * <p> * A nonzero value gives a time as the number of milliseconds since * January 1, 1970, GMT. The object is fetched only if it has been * modified more recently than that time. * <p> * This variable is set by the {@code setIfModifiedSince} * method. Its value is returned by the * {@code getIfModifiedSince} method. * <p> * The default value of this field is {@code 0}, indicating * that the fetching must always occur. * * @see java.net.URLConnection#getIfModifiedSince() * @see java.net.URLConnection#setIfModifiedSince(long) */
protected long ifModifiedSince = 0;
If false, this connection object has not created a communications link to the specified URL. If true, the communications link has been established.
/** * If {@code false}, this connection object has not created a * communications link to the specified URL. If {@code true}, * the communications link has been established. */
protected boolean connected = false;
Since:1.5
/** * @since 1.5 */
private int connectTimeout; private int readTimeout;
Since:1.6
/** * @since 1.6 */
private MessageHeader requests;
Since: JDK1.1
/** * @since JDK1.1 */
private static FileNameMap fileNameMap;
Since:1.2.2
/** * @since 1.2.2 */
private static boolean fileNameMapLoaded = false;
Loads filename map (a mimetable) from a data file. It will first try to load the user-specific table, defined by "content.types.user.table" property. If that fails, it tries to load the default built-in table.
See Also:
Returns:the FileNameMap
Since:1.2
/** * Loads filename map (a mimetable) from a data file. It will * first try to load the user-specific table, defined * by &quot;content.types.user.table&quot; property. If that fails, * it tries to load the default built-in table. * * @return the FileNameMap * @since 1.2 * @see #setFileNameMap(java.net.FileNameMap) */
public static synchronized FileNameMap getFileNameMap() { if ((fileNameMap == null) && !fileNameMapLoaded) { fileNameMap = sun.net.www.MimeTable.loadTable(); fileNameMapLoaded = true; } return new FileNameMap() { private FileNameMap map = fileNameMap; public String getContentTypeFor(String fileName) { return map.getContentTypeFor(fileName); } }; }
Sets the FileNameMap.

If there is a security manager, this method first calls the security manager's checkSetFactory method to ensure the operation is allowed. This could result in a SecurityException.

Params:
  • map – the FileNameMap to be set
Throws:
  • SecurityException – if a security manager exists and its checkSetFactory method doesn't allow the operation.
See Also:
Since:1.2
/** * Sets the FileNameMap. * <p> * If there is a security manager, this method first calls * the security manager's {@code checkSetFactory} method * to ensure the operation is allowed. * This could result in a SecurityException. * * @param map the FileNameMap to be set * @exception SecurityException if a security manager exists and its * {@code checkSetFactory} method doesn't allow the operation. * @see SecurityManager#checkSetFactory * @see #getFileNameMap() * @since 1.2 */
public static void setFileNameMap(FileNameMap map) { SecurityManager sm = System.getSecurityManager(); if (sm != null) sm.checkSetFactory(); fileNameMap = map; }
Opens a communications link to the resource referenced by this URL, if such a connection has not already been established.

If the connect method is called when the connection has already been opened (indicated by the connected field having the value true), the call is ignored.

URLConnection objects go through two phases: first they are created, then they are connected. After being created, and before being connected, various options can be specified (e.g., doInput and UseCaches). After connecting, it is an error to try to set them. Operations that depend on being connected, like getContentLength, will implicitly perform the connection, if necessary.

Throws:
See Also:
/** * Opens a communications link to the resource referenced by this * URL, if such a connection has not already been established. * <p> * If the {@code connect} method is called when the connection * has already been opened (indicated by the {@code connected} * field having the value {@code true}), the call is ignored. * <p> * URLConnection objects go through two phases: first they are * created, then they are connected. After being created, and * before being connected, various options can be specified * (e.g., doInput and UseCaches). After connecting, it is an * error to try to set them. Operations that depend on being * connected, like getContentLength, will implicitly perform the * connection, if necessary. * * @throws SocketTimeoutException if the timeout expires before * the connection can be established * @exception IOException if an I/O error occurs while opening the * connection. * @see java.net.URLConnection#connected * @see #getConnectTimeout() * @see #setConnectTimeout(int) */
abstract public void connect() throws IOException;
Sets a specified timeout value, in milliseconds, to be used when opening a communications link to the resource referenced by this URLConnection. If the timeout expires before the connection can be established, a java.net.SocketTimeoutException is raised. A timeout of zero is interpreted as an infinite timeout.

Some non-standard implementation of this method may ignore the specified timeout. To see the connect timeout set, please call getConnectTimeout().

Params:
  • timeout – an int that specifies the connect timeout value in milliseconds
Throws:
See Also:
Since:1.5
/** * Sets a specified timeout value, in milliseconds, to be used * when opening a communications link to the resource referenced * by this URLConnection. If the timeout expires before the * connection can be established, a * java.net.SocketTimeoutException is raised. A timeout of zero is * interpreted as an infinite timeout. * <p> Some non-standard implementation of this method may ignore * the specified timeout. To see the connect timeout set, please * call getConnectTimeout(). * * @param timeout an {@code int} that specifies the connect * timeout value in milliseconds * @throws IllegalArgumentException if the timeout parameter is negative * * @see #getConnectTimeout() * @see #connect() * @since 1.5 */
public void setConnectTimeout(int timeout) { if (timeout < 0) { throw new IllegalArgumentException("timeout can not be negative"); } connectTimeout = timeout; }
Returns setting for connect timeout.

0 return implies that the option is disabled (i.e., timeout of infinity).

See Also:
Returns:an int that indicates the connect timeout value in milliseconds
Since:1.5
/** * Returns setting for connect timeout. * <p> * 0 return implies that the option is disabled * (i.e., timeout of infinity). * * @return an {@code int} that indicates the connect timeout * value in milliseconds * @see #setConnectTimeout(int) * @see #connect() * @since 1.5 */
public int getConnectTimeout() { return connectTimeout; }
Sets the read timeout to a specified timeout, in milliseconds. A non-zero value specifies the timeout when reading from Input stream when a connection is established to a resource. If the timeout expires before there is data available for read, a java.net.SocketTimeoutException is raised. A timeout of zero is interpreted as an infinite timeout.

Some non-standard implementation of this method ignores the specified timeout. To see the read timeout set, please call getReadTimeout().

Params:
  • timeout – an int that specifies the timeout value to be used in milliseconds
Throws:
See Also:
Since:1.5
/** * Sets the read timeout to a specified timeout, in * milliseconds. A non-zero value specifies the timeout when * reading from Input stream when a connection is established to a * resource. If the timeout expires before there is data available * for read, a java.net.SocketTimeoutException is raised. A * timeout of zero is interpreted as an infinite timeout. * *<p> Some non-standard implementation of this method ignores the * specified timeout. To see the read timeout set, please call * getReadTimeout(). * * @param timeout an {@code int} that specifies the timeout * value to be used in milliseconds * @throws IllegalArgumentException if the timeout parameter is negative * * @see #getReadTimeout() * @see InputStream#read() * @since 1.5 */
public void setReadTimeout(int timeout) { if (timeout < 0) { throw new IllegalArgumentException("timeout can not be negative"); } readTimeout = timeout; }
Returns setting for read timeout. 0 return implies that the option is disabled (i.e., timeout of infinity).
See Also:
Returns:an int that indicates the read timeout value in milliseconds
Since:1.5
/** * Returns setting for read timeout. 0 return implies that the * option is disabled (i.e., timeout of infinity). * * @return an {@code int} that indicates the read timeout * value in milliseconds * * @see #setReadTimeout(int) * @see InputStream#read() * @since 1.5 */
public int getReadTimeout() { return readTimeout; }
Constructs a URL connection to the specified URL. A connection to the object referenced by the URL is not created.
Params:
  • url – the specified URL.
/** * Constructs a URL connection to the specified URL. A connection to * the object referenced by the URL is not created. * * @param url the specified URL. */
protected URLConnection(URL url) { this.url = url; }
Returns the value of this URLConnection's URL field.
See Also:
Returns: the value of this URLConnection's URL field.
/** * Returns the value of this {@code URLConnection}'s {@code URL} * field. * * @return the value of this {@code URLConnection}'s {@code URL} * field. * @see java.net.URLConnection#url */
public URL getURL() { return url; }
Returns the value of the content-length header field.

Note: getContentLengthLong() should be preferred over this method, since it returns a long instead and is therefore more portable.

Returns: the content length of the resource that this connection's URL references, -1 if the content length is not known, or if the content length is greater than Integer.MAX_VALUE.
/** * Returns the value of the {@code content-length} header field. * <P> * <B>Note</B>: {@link #getContentLengthLong() getContentLengthLong()} * should be preferred over this method, since it returns a {@code long} * instead and is therefore more portable.</P> * * @return the content length of the resource that this connection's URL * references, {@code -1} if the content length is not known, * or if the content length is greater than Integer.MAX_VALUE. */
public int getContentLength() { long l = getContentLengthLong(); if (l > Integer.MAX_VALUE) return -1; return (int) l; }
Returns the value of the content-length header field as a long.
Returns: the content length of the resource that this connection's URL references, or -1 if the content length is not known.
Since:7.0
/** * Returns the value of the {@code content-length} header field as a * long. * * @return the content length of the resource that this connection's URL * references, or {@code -1} if the content length is * not known. * @since 7.0 */
public long getContentLengthLong() { return getHeaderFieldLong("content-length", -1); }
Returns the value of the content-type header field.
See Also:
Returns: the content type of the resource that the URL references, or null if not known.
/** * Returns the value of the {@code content-type} header field. * * @return the content type of the resource that the URL references, * or {@code null} if not known. * @see java.net.URLConnection#getHeaderField(java.lang.String) */
public String getContentType() { return getHeaderField("content-type"); }
Returns the value of the content-encoding header field.
See Also:
Returns: the content encoding of the resource that the URL references, or null if not known.
/** * Returns the value of the {@code content-encoding} header field. * * @return the content encoding of the resource that the URL references, * or {@code null} if not known. * @see java.net.URLConnection#getHeaderField(java.lang.String) */
public String getContentEncoding() { return getHeaderField("content-encoding"); }
Returns the value of the expires header field.
See Also:
Returns: the expiration date of the resource that this URL references, or 0 if not known. The value is the number of milliseconds since January 1, 1970 GMT.
/** * Returns the value of the {@code expires} header field. * * @return the expiration date of the resource that this URL references, * or 0 if not known. The value is the number of milliseconds since * January 1, 1970 GMT. * @see java.net.URLConnection#getHeaderField(java.lang.String) */
public long getExpiration() { return getHeaderFieldDate("expires", 0); }
Returns the value of the date header field.
See Also:
Returns: the sending date of the resource that the URL references, or 0 if not known. The value returned is the number of milliseconds since January 1, 1970 GMT.
/** * Returns the value of the {@code date} header field. * * @return the sending date of the resource that the URL references, * or {@code 0} if not known. The value returned is the * number of milliseconds since January 1, 1970 GMT. * @see java.net.URLConnection#getHeaderField(java.lang.String) */
public long getDate() { return getHeaderFieldDate("date", 0); }
Returns the value of the last-modified header field. The result is the number of milliseconds since January 1, 1970 GMT.
See Also:
Returns: the date the resource referenced by this URLConnection was last modified, or 0 if not known.
/** * Returns the value of the {@code last-modified} header field. * The result is the number of milliseconds since January 1, 1970 GMT. * * @return the date the resource referenced by this * {@code URLConnection} was last modified, or 0 if not known. * @see java.net.URLConnection#getHeaderField(java.lang.String) */
public long getLastModified() { return getHeaderFieldDate("last-modified", 0); }
Returns the value of the named header field.

If called on a connection that sets the same header multiple times with possibly different values, only the last value is returned.

Params:
  • name – the name of a header field.
Returns: the value of the named header field, or null if there is no such field in the header.
/** * Returns the value of the named header field. * <p> * If called on a connection that sets the same header multiple times * with possibly different values, only the last value is returned. * * * @param name the name of a header field. * @return the value of the named header field, or {@code null} * if there is no such field in the header. */
public String getHeaderField(String name) { return null; }
Returns an unmodifiable Map of the header fields. The Map keys are Strings that represent the response-header field names. Each Map value is an unmodifiable List of Strings that represents the corresponding field values.
Returns:a Map of header fields
Since:1.4
/** * Returns an unmodifiable Map of the header fields. * The Map keys are Strings that represent the * response-header field names. Each Map value is an * unmodifiable List of Strings that represents * the corresponding field values. * * @return a Map of header fields * @since 1.4 */
public Map<String,List<String>> getHeaderFields() { return Collections.emptyMap(); }
Returns the value of the named field parsed as a number.

This form of getHeaderField exists because some connection types (e.g., http-ng) have pre-parsed headers. Classes for that connection type can override this method and short-circuit the parsing.

Params:
  • name – the name of the header field.
  • Default – the default value.
Returns: the value of the named field, parsed as an integer. The Default value is returned if the field is missing or malformed.
/** * Returns the value of the named field parsed as a number. * <p> * This form of {@code getHeaderField} exists because some * connection types (e.g., {@code http-ng}) have pre-parsed * headers. Classes for that connection type can override this method * and short-circuit the parsing. * * @param name the name of the header field. * @param Default the default value. * @return the value of the named field, parsed as an integer. The * {@code Default} value is returned if the field is * missing or malformed. */
public int getHeaderFieldInt(String name, int Default) { String value = getHeaderField(name); try { return Integer.parseInt(value); } catch (Exception e) { } return Default; }
Returns the value of the named field parsed as a number.

This form of getHeaderField exists because some connection types (e.g., http-ng) have pre-parsed headers. Classes for that connection type can override this method and short-circuit the parsing.

Params:
  • name – the name of the header field.
  • Default – the default value.
Returns: the value of the named field, parsed as a long. The Default value is returned if the field is missing or malformed.
Since:7.0
/** * Returns the value of the named field parsed as a number. * <p> * This form of {@code getHeaderField} exists because some * connection types (e.g., {@code http-ng}) have pre-parsed * headers. Classes for that connection type can override this method * and short-circuit the parsing. * * @param name the name of the header field. * @param Default the default value. * @return the value of the named field, parsed as a long. The * {@code Default} value is returned if the field is * missing or malformed. * @since 7.0 */
public long getHeaderFieldLong(String name, long Default) { String value = getHeaderField(name); try { return Long.parseLong(value); } catch (Exception e) { } return Default; }
Returns the value of the named field parsed as date. The result is the number of milliseconds since January 1, 1970 GMT represented by the named field.

This form of getHeaderField exists because some connection types (e.g., http-ng) have pre-parsed headers. Classes for that connection type can override this method and short-circuit the parsing.

Params:
  • name – the name of the header field.
  • Default – a default value.
Returns: the value of the field, parsed as a date. The value of the Default argument is returned if the field is missing or malformed.
/** * Returns the value of the named field parsed as date. * The result is the number of milliseconds since January 1, 1970 GMT * represented by the named field. * <p> * This form of {@code getHeaderField} exists because some * connection types (e.g., {@code http-ng}) have pre-parsed * headers. Classes for that connection type can override this method * and short-circuit the parsing. * * @param name the name of the header field. * @param Default a default value. * @return the value of the field, parsed as a date. The value of the * {@code Default} argument is returned if the field is * missing or malformed. */
@SuppressWarnings("deprecation") public long getHeaderFieldDate(String name, long Default) { String value = getHeaderField(name); try { return Date.parse(value); } catch (Exception e) { } return Default; }
Returns the key for the nth header field. It returns null if there are fewer than n+1 fields.
Params:
  • n – an index, where n>=0
Returns: the key for the nth header field, or null if there are fewer than n+1 fields.
/** * Returns the key for the {@code n}<sup>th</sup> header field. * It returns {@code null} if there are fewer than {@code n+1} fields. * * @param n an index, where {@code n>=0} * @return the key for the {@code n}<sup>th</sup> header field, * or {@code null} if there are fewer than {@code n+1} * fields. */
public String getHeaderFieldKey(int n) { return null; }
Returns the value for the nth header field. It returns null if there are fewer than n+1fields.

This method can be used in conjunction with the getHeaderFieldKey method to iterate through all the headers in the message.

Params:
  • n – an index, where n>=0
See Also:
Returns: the value of the nth header field or null if there are fewer than n+1 fields
/** * Returns the value for the {@code n}<sup>th</sup> header field. * It returns {@code null} if there are fewer than * {@code n+1}fields. * <p> * This method can be used in conjunction with the * {@link #getHeaderFieldKey(int) getHeaderFieldKey} method to iterate through all * the headers in the message. * * @param n an index, where {@code n>=0} * @return the value of the {@code n}<sup>th</sup> header field * or {@code null} if there are fewer than {@code n+1} fields * @see java.net.URLConnection#getHeaderFieldKey(int) */
public String getHeaderField(int n) { return null; }
Retrieves the contents of this URL connection.

This method first determines the content type of the object by calling the getContentType method. If this is the first time that the application has seen that specific content type, a content handler for that content type is created:

  1. If the application has set up a content handler factory instance using the setContentHandlerFactory method, the createContentHandler method of that instance is called with the content type as an argument; the result is a content handler for that content type.
  2. If no content handler factory has yet been set up, or if the factory's createContentHandler method returns null, then the application loads the class named:
            sun.net.www.content.<contentType>
        
    where <contentType> is formed by taking the content-type string, replacing all slash characters with a period ('.'), and all other non-alphanumeric characters with the underscore character '_'. The alphanumeric characters are specifically the 26 uppercase ASCII letters 'A' through 'Z', the 26 lowercase ASCII letters 'a' through 'z', and the 10 ASCII digits '0' through '9'. If the specified class does not exist, or is not a subclass of ContentHandler, then an UnknownServiceException is thrown.
Throws:
See Also:
Returns: the object fetched. The instanceof operator should be used to determine the specific kind of object returned.
/** * Retrieves the contents of this URL connection. * <p> * This method first determines the content type of the object by * calling the {@code getContentType} method. If this is * the first time that the application has seen that specific content * type, a content handler for that content type is created: * <ol> * <li>If the application has set up a content handler factory instance * using the {@code setContentHandlerFactory} method, the * {@code createContentHandler} method of that instance is called * with the content type as an argument; the result is a content * handler for that content type. * <li>If no content handler factory has yet been set up, or if the * factory's {@code createContentHandler} method returns * {@code null}, then the application loads the class named: * <blockquote><pre> * sun.net.www.content.&lt;<i>contentType</i>&gt; * </pre></blockquote> * where &lt;<i>contentType</i>&gt; is formed by taking the * content-type string, replacing all slash characters with a * {@code period} ('.'), and all other non-alphanumeric characters * with the underscore character '{@code _}'. The alphanumeric * characters are specifically the 26 uppercase ASCII letters * '{@code A}' through '{@code Z}', the 26 lowercase ASCII * letters '{@code a}' through '{@code z}', and the 10 ASCII * digits '{@code 0}' through '{@code 9}'. If the specified * class does not exist, or is not a subclass of * {@code ContentHandler}, then an * {@code UnknownServiceException} is thrown. * </ol> * * @return the object fetched. The {@code instanceof} operator * should be used to determine the specific kind of object * returned. * @exception IOException if an I/O error occurs while * getting the content. * @exception UnknownServiceException if the protocol does not support * the content type. * @see java.net.ContentHandlerFactory#createContentHandler(java.lang.String) * @see java.net.URLConnection#getContentType() * @see java.net.URLConnection#setContentHandlerFactory(java.net.ContentHandlerFactory) */
public Object getContent() throws IOException { // Must call getInputStream before GetHeaderField gets called // so that FileNotFoundException has a chance to be thrown up // from here without being caught. getInputStream(); return getContentHandler().getContent(this); }
Retrieves the contents of this URL connection.
Params:
  • classes – the Class array indicating the requested types
Throws:
See Also:
Returns: the object fetched that is the first match of the type specified in the classes array. null if none of the requested types are supported. The instanceof operator should be used to determine the specific kind of object returned.
Since:1.3
/** * Retrieves the contents of this URL connection. * * @param classes the {@code Class} array * indicating the requested types * @return the object fetched that is the first match of the type * specified in the classes array. null if none of * the requested types are supported. * The {@code instanceof} operator should be used to * determine the specific kind of object returned. * @exception IOException if an I/O error occurs while * getting the content. * @exception UnknownServiceException if the protocol does not support * the content type. * @see java.net.URLConnection#getContent() * @see java.net.ContentHandlerFactory#createContentHandler(java.lang.String) * @see java.net.URLConnection#getContent(java.lang.Class[]) * @see java.net.URLConnection#setContentHandlerFactory(java.net.ContentHandlerFactory) * @since 1.3 */
public Object getContent(Class[] classes) throws IOException { // Must call getInputStream before GetHeaderField gets called // so that FileNotFoundException has a chance to be thrown up // from here without being caught. getInputStream(); return getContentHandler().getContent(this, classes); }
Returns a permission object representing the permission necessary to make the connection represented by this object. This method returns null if no permission is required to make the connection. By default, this method returns java.security.AllPermission. Subclasses should override this method and return the permission that best represents the permission required to make a a connection to the URL. For example, a URLConnection representing a file: URL would return a java.io.FilePermission object.

The permission returned may dependent upon the state of the connection. For example, the permission before connecting may be different from that after connecting. For example, an HTTP sever, say foo.com, may redirect the connection to a different host, say bar.com. Before connecting the permission returned by the connection will represent the permission needed to connect to foo.com, while the permission returned after connecting will be to bar.com.

Permissions are generally used for two purposes: to protect caches of objects obtained through URLConnections, and to check the right of a recipient to learn about a particular URL. In the first case, the permission should be obtained after the object has been obtained. For example, in an HTTP connection, this will represent the permission to connect to the host from which the data was ultimately fetched. In the second case, the permission should be obtained and tested before connecting.

Throws:
  • IOException – if the computation of the permission requires network or file I/O and an exception occurs while computing it.
Returns:the permission object representing the permission necessary to make the connection represented by this URLConnection.
/** * Returns a permission object representing the permission * necessary to make the connection represented by this * object. This method returns null if no permission is * required to make the connection. By default, this method * returns {@code java.security.AllPermission}. Subclasses * should override this method and return the permission * that best represents the permission required to make a * a connection to the URL. For example, a {@code URLConnection} * representing a {@code file:} URL would return a * {@code java.io.FilePermission} object. * * <p>The permission returned may dependent upon the state of the * connection. For example, the permission before connecting may be * different from that after connecting. For example, an HTTP * sever, say foo.com, may redirect the connection to a different * host, say bar.com. Before connecting the permission returned by * the connection will represent the permission needed to connect * to foo.com, while the permission returned after connecting will * be to bar.com. * * <p>Permissions are generally used for two purposes: to protect * caches of objects obtained through URLConnections, and to check * the right of a recipient to learn about a particular URL. In * the first case, the permission should be obtained * <em>after</em> the object has been obtained. For example, in an * HTTP connection, this will represent the permission to connect * to the host from which the data was ultimately fetched. In the * second case, the permission should be obtained and tested * <em>before</em> connecting. * * @return the permission object representing the permission * necessary to make the connection represented by this * URLConnection. * * @exception IOException if the computation of the permission * requires network or file I/O and an exception occurs while * computing it. */
public Permission getPermission() throws IOException { return SecurityConstants.ALL_PERMISSION; }
Returns an input stream that reads from this open connection. A SocketTimeoutException can be thrown when reading from the returned input stream if the read timeout expires before data is available for read.
Throws:
See Also:
Returns: an input stream that reads from this open connection.
/** * Returns an input stream that reads from this open connection. * * A SocketTimeoutException can be thrown when reading from the * returned input stream if the read timeout expires before data * is available for read. * * @return an input stream that reads from this open connection. * @exception IOException if an I/O error occurs while * creating the input stream. * @exception UnknownServiceException if the protocol does not support * input. * @see #setReadTimeout(int) * @see #getReadTimeout() */
public InputStream getInputStream() throws IOException { throw new UnknownServiceException("protocol doesn't support input"); }
Returns an output stream that writes to this connection.
Throws:
Returns: an output stream that writes to this connection.
/** * Returns an output stream that writes to this connection. * * @return an output stream that writes to this connection. * @exception IOException if an I/O error occurs while * creating the output stream. * @exception UnknownServiceException if the protocol does not support * output. */
public OutputStream getOutputStream() throws IOException { throw new UnknownServiceException("protocol doesn't support output"); }
Returns a String representation of this URL connection.
Returns: a string representation of this URLConnection.
/** * Returns a {@code String} representation of this URL connection. * * @return a string representation of this {@code URLConnection}. */
public String toString() { return this.getClass().getName() + ":" + url; }
Sets the value of the doInput field for this URLConnection to the specified value.

A URL connection can be used for input and/or output. Set the DoInput flag to true if you intend to use the URL connection for input, false if not. The default is true.

Params:
  • doinput – the new value.
Throws:
See Also:
/** * Sets the value of the {@code doInput} field for this * {@code URLConnection} to the specified value. * <p> * A URL connection can be used for input and/or output. Set the DoInput * flag to true if you intend to use the URL connection for input, * false if not. The default is true. * * @param doinput the new value. * @throws IllegalStateException if already connected * @see java.net.URLConnection#doInput * @see #getDoInput() */
public void setDoInput(boolean doinput) { if (connected) throw new IllegalStateException("Already connected"); doInput = doinput; }
Returns the value of this URLConnection's doInput flag.
See Also:
Returns: the value of this URLConnection's doInput flag.
/** * Returns the value of this {@code URLConnection}'s * {@code doInput} flag. * * @return the value of this {@code URLConnection}'s * {@code doInput} flag. * @see #setDoInput(boolean) */
public boolean getDoInput() { return doInput; }
Sets the value of the doOutput field for this URLConnection to the specified value.

A URL connection can be used for input and/or output. Set the DoOutput flag to true if you intend to use the URL connection for output, false if not. The default is false.

Params:
  • dooutput – the new value.
Throws:
See Also:
/** * Sets the value of the {@code doOutput} field for this * {@code URLConnection} to the specified value. * <p> * A URL connection can be used for input and/or output. Set the DoOutput * flag to true if you intend to use the URL connection for output, * false if not. The default is false. * * @param dooutput the new value. * @throws IllegalStateException if already connected * @see #getDoOutput() */
public void setDoOutput(boolean dooutput) { if (connected) throw new IllegalStateException("Already connected"); doOutput = dooutput; }
Returns the value of this URLConnection's doOutput flag.
See Also:
Returns: the value of this URLConnection's doOutput flag.
/** * Returns the value of this {@code URLConnection}'s * {@code doOutput} flag. * * @return the value of this {@code URLConnection}'s * {@code doOutput} flag. * @see #setDoOutput(boolean) */
public boolean getDoOutput() { return doOutput; }
Set the value of the allowUserInteraction field of this URLConnection.
Params:
  • allowuserinteraction – the new value.
Throws:
See Also:
/** * Set the value of the {@code allowUserInteraction} field of * this {@code URLConnection}. * * @param allowuserinteraction the new value. * @throws IllegalStateException if already connected * @see #getAllowUserInteraction() */
public void setAllowUserInteraction(boolean allowuserinteraction) { if (connected) throw new IllegalStateException("Already connected"); allowUserInteraction = allowuserinteraction; }
Returns the value of the allowUserInteraction field for this object.
See Also:
Returns: the value of the allowUserInteraction field for this object.
/** * Returns the value of the {@code allowUserInteraction} field for * this object. * * @return the value of the {@code allowUserInteraction} field for * this object. * @see #setAllowUserInteraction(boolean) */
public boolean getAllowUserInteraction() { return allowUserInteraction; }
Sets the default value of the allowUserInteraction field for all future URLConnection objects to the specified value.
Params:
  • defaultallowuserinteraction – the new value.
See Also:
/** * Sets the default value of the * {@code allowUserInteraction} field for all future * {@code URLConnection} objects to the specified value. * * @param defaultallowuserinteraction the new value. * @see #getDefaultAllowUserInteraction() */
public static void setDefaultAllowUserInteraction(boolean defaultallowuserinteraction) { defaultAllowUserInteraction = defaultallowuserinteraction; }
Returns the default value of the allowUserInteraction field.

Ths default is "sticky", being a part of the static state of all URLConnections. This flag applies to the next, and all following URLConnections that are created.

See Also:
Returns: the default value of the allowUserInteraction field.
/** * Returns the default value of the {@code allowUserInteraction} * field. * <p> * Ths default is "sticky", being a part of the static state of all * URLConnections. This flag applies to the next, and all following * URLConnections that are created. * * @return the default value of the {@code allowUserInteraction} * field. * @see #setDefaultAllowUserInteraction(boolean) */
public static boolean getDefaultAllowUserInteraction() { return defaultAllowUserInteraction; }
Sets the value of the useCaches field of this URLConnection to the specified value.

Some protocols do caching of documents. Occasionally, it is important to be able to "tunnel through" and ignore the caches (e.g., the "reload" button in a browser). If the UseCaches flag on a connection is true, the connection is allowed to use whatever caches it can. If false, caches are to be ignored. The default value comes from DefaultUseCaches, which defaults to true.

Params:
  • usecaches – a boolean indicating whether or not to allow caching
Throws:
See Also:
/** * Sets the value of the {@code useCaches} field of this * {@code URLConnection} to the specified value. * <p> * Some protocols do caching of documents. Occasionally, it is important * to be able to "tunnel through" and ignore the caches (e.g., the * "reload" button in a browser). If the UseCaches flag on a connection * is true, the connection is allowed to use whatever caches it can. * If false, caches are to be ignored. * The default value comes from DefaultUseCaches, which defaults to * true. * * @param usecaches a {@code boolean} indicating whether * or not to allow caching * @throws IllegalStateException if already connected * @see #getUseCaches() */
public void setUseCaches(boolean usecaches) { if (connected) throw new IllegalStateException("Already connected"); useCaches = usecaches; }
Returns the value of this URLConnection's useCaches field.
See Also:
Returns: the value of this URLConnection's useCaches field.
/** * Returns the value of this {@code URLConnection}'s * {@code useCaches} field. * * @return the value of this {@code URLConnection}'s * {@code useCaches} field. * @see #setUseCaches(boolean) */
public boolean getUseCaches() { return useCaches; }
Sets the value of the ifModifiedSince field of this URLConnection to the specified value.
Params:
  • ifmodifiedsince – the new value.
Throws:
See Also:
/** * Sets the value of the {@code ifModifiedSince} field of * this {@code URLConnection} to the specified value. * * @param ifmodifiedsince the new value. * @throws IllegalStateException if already connected * @see #getIfModifiedSince() */
public void setIfModifiedSince(long ifmodifiedsince) { if (connected) throw new IllegalStateException("Already connected"); ifModifiedSince = ifmodifiedsince; }
Returns the value of this object's ifModifiedSince field.
See Also:
Returns: the value of this object's ifModifiedSince field.
/** * Returns the value of this object's {@code ifModifiedSince} field. * * @return the value of this object's {@code ifModifiedSince} field. * @see #setIfModifiedSince(long) */
public long getIfModifiedSince() { return ifModifiedSince; }
Returns the default value of a URLConnection's useCaches flag.

Ths default is "sticky", being a part of the static state of all URLConnections. This flag applies to the next, and all following URLConnections that are created.

See Also:
Returns: the default value of a URLConnection's useCaches flag.
/** * Returns the default value of a {@code URLConnection}'s * {@code useCaches} flag. * <p> * Ths default is "sticky", being a part of the static state of all * URLConnections. This flag applies to the next, and all following * URLConnections that are created. * * @return the default value of a {@code URLConnection}'s * {@code useCaches} flag. * @see #setDefaultUseCaches(boolean) */
public boolean getDefaultUseCaches() { return defaultUseCaches; }
Sets the default value of the useCaches field to the specified value.
Params:
  • defaultusecaches – the new value.
See Also:
/** * Sets the default value of the {@code useCaches} field to the * specified value. * * @param defaultusecaches the new value. * @see #getDefaultUseCaches() */
public void setDefaultUseCaches(boolean defaultusecaches) { defaultUseCaches = defaultusecaches; }
Sets the general request property. If a property with the key already exists, overwrite its value with the new value.

NOTE: HTTP requires all request properties which can legally have multiple instances with the same key to use a comma-separated list syntax which enables multiple properties to be appended into a single property.

Params:
  • key – the keyword by which the request is known (e.g., "Accept").
  • value – the value associated with it.
Throws:
See Also:
/** * Sets the general request property. If a property with the key already * exists, overwrite its value with the new value. * * <p> NOTE: HTTP requires all request properties which can * legally have multiple instances with the same key * to use a comma-separated list syntax which enables multiple * properties to be appended into a single property. * * @param key the keyword by which the request is known * (e.g., "{@code Accept}"). * @param value the value associated with it. * @throws IllegalStateException if already connected * @throws NullPointerException if key is <CODE>null</CODE> * @see #getRequestProperty(java.lang.String) */
public void setRequestProperty(String key, String value) { if (connected) throw new IllegalStateException("Already connected"); if (key == null) throw new NullPointerException ("key is null"); if (requests == null) requests = new MessageHeader(); requests.set(key, value); }
Adds a general request property specified by a key-value pair. This method will not overwrite existing values associated with the same key.
Params:
  • key – the keyword by which the request is known (e.g., "Accept").
  • value – the value associated with it.
Throws:
See Also:
Since:1.4
/** * Adds a general request property specified by a * key-value pair. This method will not overwrite * existing values associated with the same key. * * @param key the keyword by which the request is known * (e.g., "{@code Accept}"). * @param value the value associated with it. * @throws IllegalStateException if already connected * @throws NullPointerException if key is null * @see #getRequestProperties() * @since 1.4 */
public void addRequestProperty(String key, String value) { if (connected) throw new IllegalStateException("Already connected"); if (key == null) throw new NullPointerException ("key is null"); if (requests == null) requests = new MessageHeader(); requests.add(key, value); }
Returns the value of the named general request property for this connection.
Params:
  • key – the keyword by which the request is known (e.g., "Accept").
Throws:
See Also:
Returns: the value of the named general request property for this connection. If key is null, then null is returned.
/** * Returns the value of the named general request property for this * connection. * * @param key the keyword by which the request is known (e.g., "Accept"). * @return the value of the named general request property for this * connection. If key is null, then null is returned. * @throws IllegalStateException if already connected * @see #setRequestProperty(java.lang.String, java.lang.String) */
public String getRequestProperty(String key) { if (connected) throw new IllegalStateException("Already connected"); if (requests == null) return null; return requests.findValue(key); }
Returns an unmodifiable Map of general request properties for this connection. The Map keys are Strings that represent the request-header field names. Each Map value is a unmodifiable List of Strings that represents the corresponding field values.
Throws:
Returns: a Map of the general request properties for this connection.
Since:1.4
/** * Returns an unmodifiable Map of general request * properties for this connection. The Map keys * are Strings that represent the request-header * field names. Each Map value is a unmodifiable List * of Strings that represents the corresponding * field values. * * @return a Map of the general request properties for this connection. * @throws IllegalStateException if already connected * @since 1.4 */
public Map<String,List<String>> getRequestProperties() { if (connected) throw new IllegalStateException("Already connected"); if (requests == null) return Collections.emptyMap(); return requests.getHeaders(null); }
Sets the default value of a general request property. When a URLConnection is created, it is initialized with these properties.
Params:
  • key – the keyword by which the request is known (e.g., "Accept").
  • value – the value associated with the key.
See Also:
Deprecated:The instance specific setRequestProperty method should be used after an appropriate instance of URLConnection is obtained. Invoking this method will have no effect.
/** * Sets the default value of a general request property. When a * {@code URLConnection} is created, it is initialized with * these properties. * * @param key the keyword by which the request is known * (e.g., "{@code Accept}"). * @param value the value associated with the key. * * @see java.net.URLConnection#setRequestProperty(java.lang.String,java.lang.String) * * @deprecated The instance specific setRequestProperty method * should be used after an appropriate instance of URLConnection * is obtained. Invoking this method will have no effect. * * @see #getDefaultRequestProperty(java.lang.String) */
@Deprecated public static void setDefaultRequestProperty(String key, String value) { }
Returns the value of the default request property. Default request properties are set for every connection.
Params:
  • key – the keyword by which the request is known (e.g., "Accept").
See Also:
Returns: the value of the default request property for the specified key.
Deprecated:The instance specific getRequestProperty method should be used after an appropriate instance of URLConnection is obtained.
/** * Returns the value of the default request property. Default request * properties are set for every connection. * * @param key the keyword by which the request is known (e.g., "Accept"). * @return the value of the default request property * for the specified key. * * @see java.net.URLConnection#getRequestProperty(java.lang.String) * * @deprecated The instance specific getRequestProperty method * should be used after an appropriate instance of URLConnection * is obtained. * * @see #setDefaultRequestProperty(java.lang.String, java.lang.String) */
@Deprecated public static String getDefaultRequestProperty(String key) { return null; }
The ContentHandler factory.
/** * The ContentHandler factory. */
static ContentHandlerFactory factory;
Sets the ContentHandlerFactory of an application. It can be called at most once by an application.

The ContentHandlerFactory instance is used to construct a content handler from a content type

If there is a security manager, this method first calls the security manager's checkSetFactory method to ensure the operation is allowed. This could result in a SecurityException.

Params:
  • fac – the desired factory.
Throws:
  • Error – if the factory has already been defined.
  • SecurityException – if a security manager exists and its checkSetFactory method doesn't allow the operation.
See Also:
/** * Sets the {@code ContentHandlerFactory} of an * application. It can be called at most once by an application. * <p> * The {@code ContentHandlerFactory} instance is used to * construct a content handler from a content type * <p> * If there is a security manager, this method first calls * the security manager's {@code checkSetFactory} method * to ensure the operation is allowed. * This could result in a SecurityException. * * @param fac the desired factory. * @exception Error if the factory has already been defined. * @exception SecurityException if a security manager exists and its * {@code checkSetFactory} method doesn't allow the operation. * @see java.net.ContentHandlerFactory * @see java.net.URLConnection#getContent() * @see SecurityManager#checkSetFactory */
public static synchronized void setContentHandlerFactory(ContentHandlerFactory fac) { if (factory != null) { throw new Error("factory already defined"); } SecurityManager security = System.getSecurityManager(); if (security != null) { security.checkSetFactory(); } factory = fac; } private static Hashtable<String, ContentHandler> handlers = new Hashtable<>();
Gets the Content Handler appropriate for this connection.
/** * Gets the Content Handler appropriate for this connection. */
synchronized ContentHandler getContentHandler() throws UnknownServiceException { String contentType = stripOffParameters(getContentType()); ContentHandler handler = null; if (contentType == null) throw new UnknownServiceException("no content-type"); try { handler = handlers.get(contentType); if (handler != null) return handler; } catch(Exception e) { } if (factory != null) handler = factory.createContentHandler(contentType); if (handler == null) { try { handler = lookupContentHandlerClassFor(contentType); } catch(Exception e) { e.printStackTrace(); handler = UnknownContentHandler.INSTANCE; } handlers.put(contentType, handler); } return handler; } /* * Media types are in the format: type/subtype*(; parameter). * For looking up the content handler, we should ignore those * parameters. */ private String stripOffParameters(String contentType) { if (contentType == null) return null; int index = contentType.indexOf(';'); if (index > 0) return contentType.substring(0, index); else return contentType; } private static final String contentClassPrefix = "sun.net.www.content"; private static final String contentPathProp = "java.content.handler.pkgs";
Looks for a content handler in a user-defineable set of places. By default it looks in sun.net.www.content, but users can define a vertical-bar delimited set of class prefixes to search through in addition by defining the java.content.handler.pkgs property. The class name must be of the form:
    {package-prefix}.{major}.{minor}
e.g.
    YoyoDyne.experimental.text.plain
/** * Looks for a content handler in a user-defineable set of places. * By default it looks in sun.net.www.content, but users can define a * vertical-bar delimited set of class prefixes to search through in * addition by defining the java.content.handler.pkgs property. * The class name must be of the form: * <pre> * {package-prefix}.{major}.{minor} * e.g. * YoyoDyne.experimental.text.plain * </pre> */
private ContentHandler lookupContentHandlerClassFor(String contentType) throws InstantiationException, IllegalAccessException, ClassNotFoundException { String contentHandlerClassName = typeToPackageName(contentType); String contentHandlerPkgPrefixes =getContentHandlerPkgPrefixes(); StringTokenizer packagePrefixIter = new StringTokenizer(contentHandlerPkgPrefixes, "|"); while (packagePrefixIter.hasMoreTokens()) { String packagePrefix = packagePrefixIter.nextToken().trim(); try { String clsName = packagePrefix + "." + contentHandlerClassName; Class<?> cls = null; try { cls = Class.forName(clsName); } catch (ClassNotFoundException e) { ClassLoader cl = ClassLoader.getSystemClassLoader(); if (cl != null) { cls = cl.loadClass(clsName); } } if (cls != null) { ContentHandler handler = (ContentHandler)cls.newInstance(); return handler; } } catch(Exception e) { } } return UnknownContentHandler.INSTANCE; }
Utility function to map a MIME content type into an equivalent pair of class name components. For example: "text/html" would be returned as "text.html"
/** * Utility function to map a MIME content type into an equivalent * pair of class name components. For example: "text/html" would * be returned as "text.html" */
private String typeToPackageName(String contentType) { // make sure we canonicalize the class name: all lower case contentType = contentType.toLowerCase(); int len = contentType.length(); char nm[] = new char[len]; contentType.getChars(0, len, nm, 0); for (int i = 0; i < len; i++) { char c = nm[i]; if (c == '/') { nm[i] = '.'; } else if (!('A' <= c && c <= 'Z' || 'a' <= c && c <= 'z' || '0' <= c && c <= '9')) { nm[i] = '_'; } } return new String(nm); }
Returns a vertical bar separated list of package prefixes for potential content handlers. Tries to get the java.content.handler.pkgs property to use as a set of package prefixes to search. Whether or not that property has been defined, the sun.net.www.content is always the last one on the returned package list.
/** * Returns a vertical bar separated list of package prefixes for potential * content handlers. Tries to get the java.content.handler.pkgs property * to use as a set of package prefixes to search. Whether or not * that property has been defined, the sun.net.www.content is always * the last one on the returned package list. */
private String getContentHandlerPkgPrefixes() { String packagePrefixList = AccessController.doPrivileged( new sun.security.action.GetPropertyAction(contentPathProp, "")); if (packagePrefixList != "") { packagePrefixList += "|"; } return packagePrefixList + contentClassPrefix; }
Tries to determine the content type of an object, based on the specified "file" component of a URL. This is a convenience method that can be used by subclasses that override the getContentType method.
Params:
  • fname – a filename.
See Also:
Returns: a guess as to what the content type of the object is, based upon its file name.
/** * Tries to determine the content type of an object, based * on the specified "file" component of a URL. * This is a convenience method that can be used by * subclasses that override the {@code getContentType} method. * * @param fname a filename. * @return a guess as to what the content type of the object is, * based upon its file name. * @see java.net.URLConnection#getContentType() */
public static String guessContentTypeFromName(String fname) { return getFileNameMap().getContentTypeFor(fname); }
Tries to determine the type of an input stream based on the characters at the beginning of the input stream. This method can be used by subclasses that override the getContentType method.

Ideally, this routine would not be needed. But many http servers return the incorrect content type; in addition, there are many nonstandard extensions. Direct inspection of the bytes to determine the content type is often more accurate than believing the content type claimed by the http server.

Params:
  • is – an input stream that supports marks.
Throws:
  • IOException – if an I/O error occurs while reading the input stream.
See Also:
Returns: a guess at the content type, or null if none can be determined.
/** * Tries to determine the type of an input stream based on the * characters at the beginning of the input stream. This method can * be used by subclasses that override the * {@code getContentType} method. * <p> * Ideally, this routine would not be needed. But many * {@code http} servers return the incorrect content type; in * addition, there are many nonstandard extensions. Direct inspection * of the bytes to determine the content type is often more accurate * than believing the content type claimed by the {@code http} server. * * @param is an input stream that supports marks. * @return a guess at the content type, or {@code null} if none * can be determined. * @exception IOException if an I/O error occurs while reading the * input stream. * @see java.io.InputStream#mark(int) * @see java.io.InputStream#markSupported() * @see java.net.URLConnection#getContentType() */
static public String guessContentTypeFromStream(InputStream is) throws IOException { // If we can't read ahead safely, just give up on guessing if (!is.markSupported()) return null; is.mark(16); int c1 = is.read(); int c2 = is.read(); int c3 = is.read(); int c4 = is.read(); int c5 = is.read(); int c6 = is.read(); int c7 = is.read(); int c8 = is.read(); int c9 = is.read(); int c10 = is.read(); int c11 = is.read(); int c12 = is.read(); int c13 = is.read(); int c14 = is.read(); int c15 = is.read(); int c16 = is.read(); is.reset(); if (c1 == 0xCA && c2 == 0xFE && c3 == 0xBA && c4 == 0xBE) { return "application/java-vm"; } if (c1 == 0xAC && c2 == 0xED) { // next two bytes are version number, currently 0x00 0x05 return "application/x-java-serialized-object"; } if (c1 == '<') { if (c2 == '!' || ((c2 == 'h' && (c3 == 't' && c4 == 'm' && c5 == 'l' || c3 == 'e' && c4 == 'a' && c5 == 'd') || (c2 == 'b' && c3 == 'o' && c4 == 'd' && c5 == 'y'))) || ((c2 == 'H' && (c3 == 'T' && c4 == 'M' && c5 == 'L' || c3 == 'E' && c4 == 'A' && c5 == 'D') || (c2 == 'B' && c3 == 'O' && c4 == 'D' && c5 == 'Y')))) { return "text/html"; } if (c2 == '?' && c3 == 'x' && c4 == 'm' && c5 == 'l' && c6 == ' ') { return "application/xml"; } } // big and little (identical) endian UTF-8 encodings, with BOM if (c1 == 0xef && c2 == 0xbb && c3 == 0xbf) { if (c4 == '<' && c5 == '?' && c6 == 'x') { return "application/xml"; } } // big and little endian UTF-16 encodings, with byte order mark if (c1 == 0xfe && c2 == 0xff) { if (c3 == 0 && c4 == '<' && c5 == 0 && c6 == '?' && c7 == 0 && c8 == 'x') { return "application/xml"; } } if (c1 == 0xff && c2 == 0xfe) { if (c3 == '<' && c4 == 0 && c5 == '?' && c6 == 0 && c7 == 'x' && c8 == 0) { return "application/xml"; } } // big and little endian UTF-32 encodings, with BOM if (c1 == 0x00 && c2 == 0x00 && c3 == 0xfe && c4 == 0xff) { if (c5 == 0 && c6 == 0 && c7 == 0 && c8 == '<' && c9 == 0 && c10 == 0 && c11 == 0 && c12 == '?' && c13 == 0 && c14 == 0 && c15 == 0 && c16 == 'x') { return "application/xml"; } } if (c1 == 0xff && c2 == 0xfe && c3 == 0x00 && c4 == 0x00) { if (c5 == '<' && c6 == 0 && c7 == 0 && c8 == 0 && c9 == '?' && c10 == 0 && c11 == 0 && c12 == 0 && c13 == 'x' && c14 == 0 && c15 == 0 && c16 == 0) { return "application/xml"; } } if (c1 == 'G' && c2 == 'I' && c3 == 'F' && c4 == '8') { return "image/gif"; } if (c1 == '#' && c2 == 'd' && c3 == 'e' && c4 == 'f') { return "image/x-bitmap"; } if (c1 == '!' && c2 == ' ' && c3 == 'X' && c4 == 'P' && c5 == 'M' && c6 == '2') { return "image/x-pixmap"; } if (c1 == 137 && c2 == 80 && c3 == 78 && c4 == 71 && c5 == 13 && c6 == 10 && c7 == 26 && c8 == 10) { return "image/png"; } if (c1 == 0xFF && c2 == 0xD8 && c3 == 0xFF) { if (c4 == 0xE0 || c4 == 0xEE) { return "image/jpeg"; } /** * File format used by digital cameras to store images. * Exif Format can be read by any application supporting * JPEG. Exif Spec can be found at: * http://www.pima.net/standards/it10/PIMA15740/Exif_2-1.PDF */ if ((c4 == 0xE1) && (c7 == 'E' && c8 == 'x' && c9 == 'i' && c10 =='f' && c11 == 0)) { return "image/jpeg"; } } if (c1 == 0xD0 && c2 == 0xCF && c3 == 0x11 && c4 == 0xE0 && c5 == 0xA1 && c6 == 0xB1 && c7 == 0x1A && c8 == 0xE1) { /* Above is signature of Microsoft Structured Storage. * Below this, could have tests for various SS entities. * For now, just test for FlashPix. */ if (checkfpx(is)) { return "image/vnd.fpx"; } } if (c1 == 0x2E && c2 == 0x73 && c3 == 0x6E && c4 == 0x64) { return "audio/basic"; // .au format, big endian } if (c1 == 0x64 && c2 == 0x6E && c3 == 0x73 && c4 == 0x2E) { return "audio/basic"; // .au format, little endian } if (c1 == 'R' && c2 == 'I' && c3 == 'F' && c4 == 'F') { /* I don't know if this is official but evidence * suggests that .wav files start with "RIFF" - brown */ return "audio/x-wav"; } return null; }
Check for FlashPix image data in InputStream is. Return true if the stream has FlashPix data, false otherwise. Before calling this method, the stream should have already been checked to be sure it contains Microsoft Structured Storage data.
/** * Check for FlashPix image data in InputStream is. Return true if * the stream has FlashPix data, false otherwise. Before calling this * method, the stream should have already been checked to be sure it * contains Microsoft Structured Storage data. */
static private boolean checkfpx(InputStream is) throws IOException { /* Test for FlashPix image data in Microsoft Structured Storage format. * In general, should do this with calls to an SS implementation. * Lacking that, need to dig via offsets to get to the FlashPix * ClassID. Details: * * Offset to Fpx ClsID from beginning of stream should be: * * FpxClsidOffset = rootEntryOffset + clsidOffset * * where: clsidOffset = 0x50. * rootEntryOffset = headerSize + sectorSize*sectDirStart * + 128*rootEntryDirectory * * where: headerSize = 0x200 (always) * sectorSize = 2 raised to power of uSectorShift, * which is found in the header at * offset 0x1E. * sectDirStart = found in the header at offset 0x30. * rootEntryDirectory = in general, should search for * directory labelled as root. * We will assume value of 0 (i.e., * rootEntry is in first directory) */ // Mark the stream so we can reset it. 0x100 is enough for the first // few reads, but the mark will have to be reset and set again once // the offset to the root directory entry is computed. That offset // can be very large and isn't know until the stream has been read from is.mark(0x100); // Get the byte ordering located at 0x1E. 0xFE is Intel, // 0xFF is other long toSkip = (long)0x1C; long posn; if ((posn = skipForward(is, toSkip)) < toSkip) { is.reset(); return false; } int c[] = new int[16]; if (readBytes(c, 2, is) < 0) { is.reset(); return false; } int byteOrder = c[0]; posn+=2; int uSectorShift; if (readBytes(c, 2, is) < 0) { is.reset(); return false; } if(byteOrder == 0xFE) { uSectorShift = c[0]; uSectorShift += c[1] << 8; } else { uSectorShift = c[0] << 8; uSectorShift += c[1]; } posn += 2; toSkip = (long)0x30 - posn; long skipped = 0; if ((skipped = skipForward(is, toSkip)) < toSkip) { is.reset(); return false; } posn += skipped; if (readBytes(c, 4, is) < 0) { is.reset(); return false; } int sectDirStart; if(byteOrder == 0xFE) { sectDirStart = c[0]; sectDirStart += c[1] << 8; sectDirStart += c[2] << 16; sectDirStart += c[3] << 24; } else { sectDirStart = c[0] << 24; sectDirStart += c[1] << 16; sectDirStart += c[2] << 8; sectDirStart += c[3]; } posn += 4; is.reset(); // Reset back to the beginning toSkip = 0x200L + (long)(1<<uSectorShift)*sectDirStart + 0x50L; // Sanity check! if (toSkip < 0) { return false; } /* * How far can we skip? Is there any performance problem here? * This skip can be fairly long, at least 0x4c650 in at least * one case. Have to assume that the skip will fit in an int. * Leave room to read whole root dir */ is.mark((int)toSkip+0x30); if ((skipForward(is, toSkip)) < toSkip) { is.reset(); return false; } /* should be at beginning of ClassID, which is as follows * (in Intel byte order): * 00 67 61 56 54 C1 CE 11 85 53 00 AA 00 A1 F9 5B * * This is stored from Windows as long,short,short,char[8] * so for byte order changes, the order only changes for * the first 8 bytes in the ClassID. * * Test against this, ignoring second byte (Intel) since * this could change depending on part of Fpx file we have. */ if (readBytes(c, 16, is) < 0) { is.reset(); return false; } // intel byte order if (byteOrder == 0xFE && c[0] == 0x00 && c[2] == 0x61 && c[3] == 0x56 && c[4] == 0x54 && c[5] == 0xC1 && c[6] == 0xCE && c[7] == 0x11 && c[8] == 0x85 && c[9] == 0x53 && c[10]== 0x00 && c[11]== 0xAA && c[12]== 0x00 && c[13]== 0xA1 && c[14]== 0xF9 && c[15]== 0x5B) { is.reset(); return true; } // non-intel byte order else if (c[3] == 0x00 && c[1] == 0x61 && c[0] == 0x56 && c[5] == 0x54 && c[4] == 0xC1 && c[7] == 0xCE && c[6] == 0x11 && c[8] == 0x85 && c[9] == 0x53 && c[10]== 0x00 && c[11]== 0xAA && c[12]== 0x00 && c[13]== 0xA1 && c[14]== 0xF9 && c[15]== 0x5B) { is.reset(); return true; } is.reset(); return false; }
Tries to read the specified number of bytes from the stream Returns -1, If EOF is reached before len bytes are read, returns 0 otherwise
/** * Tries to read the specified number of bytes from the stream * Returns -1, If EOF is reached before len bytes are read, returns 0 * otherwise */
static private int readBytes(int c[], int len, InputStream is) throws IOException { byte buf[] = new byte[len]; if (is.read(buf, 0, len) < len) { return -1; } // fill the passed in int array for (int i = 0; i < len; i++) { c[i] = buf[i] & 0xff; } return 0; }
Skips through the specified number of bytes from the stream until either EOF is reached, or the specified number of bytes have been skipped
/** * Skips through the specified number of bytes from the stream * until either EOF is reached, or the specified * number of bytes have been skipped */
static private long skipForward(InputStream is, long toSkip) throws IOException { long eachSkip = 0; long skipped = 0; while (skipped != toSkip) { eachSkip = is.skip(toSkip - skipped); // check if EOF is reached if (eachSkip <= 0) { if (is.read() == -1) { return skipped ; } else { skipped++; } } skipped += eachSkip; } return skipped; } } class UnknownContentHandler extends ContentHandler { static final ContentHandler INSTANCE = new UnknownContentHandler(); public Object getContent(URLConnection uc) throws IOException { return uc.getInputStream(); } }