/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.commons.lang3;

import java.util.regex.Pattern;

Helpers to process Strings using regular expressions.

See Also:
  • Pattern
Since:3.8
/** * <p>Helpers to process Strings using regular expressions.</p> * @see java.util.regex.Pattern * @since 3.8 */
public class RegExUtils {

Removes each substring of the text String that matches the given regular expression pattern.

This method is a null safe equivalent to:
  • pattern.matcher(text).replaceAll(StringUtils.EMPTY)

A null reference passed to this method is a no-op.

StringUtils.removeAll(null, *)      = null
StringUtils.removeAll("any", (Pattern) null)  = "any"
StringUtils.removeAll("any", Pattern.compile(""))    = "any"
StringUtils.removeAll("any", Pattern.compile(".*"))  = ""
StringUtils.removeAll("any", Pattern.compile(".+"))  = ""
StringUtils.removeAll("abc", Pattern.compile(".?"))  = ""
StringUtils.removeAll("A<__>\n<__>B", Pattern.compile("<.*>"))      = "A\nB"
StringUtils.removeAll("A<__>\n<__>B", Pattern.compile("(?s)<.*>"))  = "AB"
StringUtils.removeAll("A<__>\n<__>B", Pattern.compile("<.*>", Pattern.DOTALL))  = "AB"
StringUtils.removeAll("ABCabc123abc", Pattern.compile("[a-z]"))     = "ABC123"
Params:
  • text – text to remove from, may be null
  • regex – the regular expression to which this string is to be matched
See Also:
Returns: the text with any removes processed, null if null String input
/** * <p>Removes each substring of the text String that matches the given regular expression pattern.</p> * * This method is a {@code null} safe equivalent to: * <ul> * <li>{@code pattern.matcher(text).replaceAll(StringUtils.EMPTY)}</li> * </ul> * * <p>A {@code null} reference passed to this method is a no-op.</p> * * <pre> * StringUtils.removeAll(null, *) = null * StringUtils.removeAll("any", (Pattern) null) = "any" * StringUtils.removeAll("any", Pattern.compile("")) = "any" * StringUtils.removeAll("any", Pattern.compile(".*")) = "" * StringUtils.removeAll("any", Pattern.compile(".+")) = "" * StringUtils.removeAll("abc", Pattern.compile(".?")) = "" * StringUtils.removeAll("A&lt;__&gt;\n&lt;__&gt;B", Pattern.compile("&lt;.*&gt;")) = "A\nB" * StringUtils.removeAll("A&lt;__&gt;\n&lt;__&gt;B", Pattern.compile("(?s)&lt;.*&gt;")) = "AB" * StringUtils.removeAll("A&lt;__&gt;\n&lt;__&gt;B", Pattern.compile("&lt;.*&gt;", Pattern.DOTALL)) = "AB" * StringUtils.removeAll("ABCabc123abc", Pattern.compile("[a-z]")) = "ABC123" * </pre> * * @param text text to remove from, may be null * @param regex the regular expression to which this string is to be matched * @return the text with any removes processed, * {@code null} if null String input * * @see #replaceAll(String, Pattern, String) * @see java.util.regex.Matcher#replaceAll(String) * @see java.util.regex.Pattern */
public static String removeAll(final String text, final Pattern regex) { return replaceAll(text, regex, StringUtils.EMPTY); }

Removes each substring of the text String that matches the given regular expression.

This method is a null safe equivalent to:
  • text.replaceAll(regex, StringUtils.EMPTY)
  • Pattern.compile(regex).matcher(text).replaceAll(StringUtils.EMPTY)

A null reference passed to this method is a no-op.

Unlike in the removePattern(String, String) method, the Pattern.DOTALL option is NOT automatically added. To use the DOTALL option prepend "(?s)" to the regex. DOTALL is also known as single-line mode in Perl.

StringUtils.removeAll(null, *)      = null
StringUtils.removeAll("any", (String) null)  = "any"
StringUtils.removeAll("any", "")    = "any"
StringUtils.removeAll("any", ".*")  = ""
StringUtils.removeAll("any", ".+")  = ""
StringUtils.removeAll("abc", ".?")  = ""
StringUtils.removeAll("A<__>\n<__>B", "<.*>")      = "A\nB"
StringUtils.removeAll("A<__>\n<__>B", "(?s)<.*>")  = "AB"
StringUtils.removeAll("ABCabc123abc", "[a-z]")     = "ABC123"
Params:
  • text – text to remove from, may be null
  • regex – the regular expression to which this string is to be matched
Throws:
See Also:
Returns: the text with any removes processed, null if null String input
/** * <p>Removes each substring of the text String that matches the given regular expression.</p> * * This method is a {@code null} safe equivalent to: * <ul> * <li>{@code text.replaceAll(regex, StringUtils.EMPTY)}</li> * <li>{@code Pattern.compile(regex).matcher(text).replaceAll(StringUtils.EMPTY)}</li> * </ul> * * <p>A {@code null} reference passed to this method is a no-op.</p> * * <p>Unlike in the {@link #removePattern(String, String)} method, the {@link Pattern#DOTALL} option * is NOT automatically added. * To use the DOTALL option prepend {@code "(?s)"} to the regex. * DOTALL is also known as single-line mode in Perl.</p> * * <pre> * StringUtils.removeAll(null, *) = null * StringUtils.removeAll("any", (String) null) = "any" * StringUtils.removeAll("any", "") = "any" * StringUtils.removeAll("any", ".*") = "" * StringUtils.removeAll("any", ".+") = "" * StringUtils.removeAll("abc", ".?") = "" * StringUtils.removeAll("A&lt;__&gt;\n&lt;__&gt;B", "&lt;.*&gt;") = "A\nB" * StringUtils.removeAll("A&lt;__&gt;\n&lt;__&gt;B", "(?s)&lt;.*&gt;") = "AB" * StringUtils.removeAll("ABCabc123abc", "[a-z]") = "ABC123" * </pre> * * @param text text to remove from, may be null * @param regex the regular expression to which this string is to be matched * @return the text with any removes processed, * {@code null} if null String input * * @throws java.util.regex.PatternSyntaxException * if the regular expression's syntax is invalid * * @see #replaceAll(String, String, String) * @see #removePattern(String, String) * @see String#replaceAll(String, String) * @see java.util.regex.Pattern * @see java.util.regex.Pattern#DOTALL */
public static String removeAll(final String text, final String regex) { return replaceAll(text, regex, StringUtils.EMPTY); }

Removes the first substring of the text string that matches the given regular expression pattern.

This method is a null safe equivalent to:
  • pattern.matcher(text).replaceFirst(StringUtils.EMPTY)

A null reference passed to this method is a no-op.

StringUtils.removeFirst(null, *)      = null
StringUtils.removeFirst("any", (Pattern) null)  = "any"
StringUtils.removeFirst("any", Pattern.compile(""))    = "any"
StringUtils.removeFirst("any", Pattern.compile(".*"))  = ""
StringUtils.removeFirst("any", Pattern.compile(".+"))  = ""
StringUtils.removeFirst("abc", Pattern.compile(".?"))  = "bc"
StringUtils.removeFirst("A<__>\n<__>B", Pattern.compile("<.*>"))      = "A\n<__>B"
StringUtils.removeFirst("A<__>\n<__>B", Pattern.compile("(?s)<.*>"))  = "AB"
StringUtils.removeFirst("ABCabc123", Pattern.compile("[a-z]"))          = "ABCbc123"
StringUtils.removeFirst("ABCabc123abc", Pattern.compile("[a-z]+"))      = "ABC123abc"
Params:
  • text – text to remove from, may be null
  • regex – the regular expression pattern to which this string is to be matched
See Also:
Returns: the text with the first replacement processed, null if null String input
/** * <p>Removes the first substring of the text string that matches the given regular expression pattern.</p> * * This method is a {@code null} safe equivalent to: * <ul> * <li>{@code pattern.matcher(text).replaceFirst(StringUtils.EMPTY)}</li> * </ul> * * <p>A {@code null} reference passed to this method is a no-op.</p> * * <pre> * StringUtils.removeFirst(null, *) = null * StringUtils.removeFirst("any", (Pattern) null) = "any" * StringUtils.removeFirst("any", Pattern.compile("")) = "any" * StringUtils.removeFirst("any", Pattern.compile(".*")) = "" * StringUtils.removeFirst("any", Pattern.compile(".+")) = "" * StringUtils.removeFirst("abc", Pattern.compile(".?")) = "bc" * StringUtils.removeFirst("A&lt;__&gt;\n&lt;__&gt;B", Pattern.compile("&lt;.*&gt;")) = "A\n&lt;__&gt;B" * StringUtils.removeFirst("A&lt;__&gt;\n&lt;__&gt;B", Pattern.compile("(?s)&lt;.*&gt;")) = "AB" * StringUtils.removeFirst("ABCabc123", Pattern.compile("[a-z]")) = "ABCbc123" * StringUtils.removeFirst("ABCabc123abc", Pattern.compile("[a-z]+")) = "ABC123abc" * </pre> * * @param text text to remove from, may be null * @param regex the regular expression pattern to which this string is to be matched * @return the text with the first replacement processed, * {@code null} if null String input * * @see #replaceFirst(String, Pattern, String) * @see java.util.regex.Matcher#replaceFirst(String) * @see java.util.regex.Pattern */
public static String removeFirst(final String text, final Pattern regex) { return replaceFirst(text, regex, StringUtils.EMPTY); }

Removes the first substring of the text string that matches the given regular expression.

This method is a null safe equivalent to:
  • text.replaceFirst(regex, StringUtils.EMPTY)
  • Pattern.compile(regex).matcher(text).replaceFirst(StringUtils.EMPTY)

A null reference passed to this method is a no-op.

The Pattern.DOTALL option is NOT automatically added. To use the DOTALL option prepend "(?s)" to the regex. DOTALL is also known as single-line mode in Perl.

StringUtils.removeFirst(null, *)      = null
StringUtils.removeFirst("any", (String) null)  = "any"
StringUtils.removeFirst("any", "")    = "any"
StringUtils.removeFirst("any", ".*")  = ""
StringUtils.removeFirst("any", ".+")  = ""
StringUtils.removeFirst("abc", ".?")  = "bc"
StringUtils.removeFirst("A<__>\n<__>B", "<.*>")      = "A\n<__>B"
StringUtils.removeFirst("A<__>\n<__>B", "(?s)<.*>")  = "AB"
StringUtils.removeFirst("ABCabc123", "[a-z]")          = "ABCbc123"
StringUtils.removeFirst("ABCabc123abc", "[a-z]+")      = "ABC123abc"
Params:
  • text – text to remove from, may be null
  • regex – the regular expression to which this string is to be matched
Throws:
See Also:
Returns: the text with the first replacement processed, null if null String input
/** * <p>Removes the first substring of the text string that matches the given regular expression.</p> * * This method is a {@code null} safe equivalent to: * <ul> * <li>{@code text.replaceFirst(regex, StringUtils.EMPTY)}</li> * <li>{@code Pattern.compile(regex).matcher(text).replaceFirst(StringUtils.EMPTY)}</li> * </ul> * * <p>A {@code null} reference passed to this method is a no-op.</p> * * <p>The {@link Pattern#DOTALL} option is NOT automatically added. * To use the DOTALL option prepend {@code "(?s)"} to the regex. * DOTALL is also known as single-line mode in Perl.</p> * * <pre> * StringUtils.removeFirst(null, *) = null * StringUtils.removeFirst("any", (String) null) = "any" * StringUtils.removeFirst("any", "") = "any" * StringUtils.removeFirst("any", ".*") = "" * StringUtils.removeFirst("any", ".+") = "" * StringUtils.removeFirst("abc", ".?") = "bc" * StringUtils.removeFirst("A&lt;__&gt;\n&lt;__&gt;B", "&lt;.*&gt;") = "A\n&lt;__&gt;B" * StringUtils.removeFirst("A&lt;__&gt;\n&lt;__&gt;B", "(?s)&lt;.*&gt;") = "AB" * StringUtils.removeFirst("ABCabc123", "[a-z]") = "ABCbc123" * StringUtils.removeFirst("ABCabc123abc", "[a-z]+") = "ABC123abc" * </pre> * * @param text text to remove from, may be null * @param regex the regular expression to which this string is to be matched * @return the text with the first replacement processed, * {@code null} if null String input * * @throws java.util.regex.PatternSyntaxException * if the regular expression's syntax is invalid * * @see #replaceFirst(String, String, String) * @see String#replaceFirst(String, String) * @see java.util.regex.Pattern * @see java.util.regex.Pattern#DOTALL */
public static String removeFirst(final String text, final String regex) { return replaceFirst(text, regex, StringUtils.EMPTY); }

Removes each substring of the source String that matches the given regular expression using the DOTALL option.

This call is a null safe equivalent to:
  • text.replaceAll(&quot;(?s)&quot; + regex, StringUtils.EMPTY)
  • Pattern.compile(regex, Pattern.DOTALL).matcher(text).replaceAll(StringUtils.EMPTY)

A null reference passed to this method is a no-op.

StringUtils.removePattern(null, *)       = null
StringUtils.removePattern("any", (String) null)   = "any"
StringUtils.removePattern("A<__>\n<__>B", "<.*>")  = "AB"
StringUtils.removePattern("ABCabc123", "[a-z]")    = "ABC123"
Params:
  • text – the source string
  • regex – the regular expression to which this string is to be matched
See Also:
Returns:The resulting String
/** * <p>Removes each substring of the source String that matches the given regular expression using the DOTALL option.</p> * * This call is a {@code null} safe equivalent to: * <ul> * <li>{@code text.replaceAll(&quot;(?s)&quot; + regex, StringUtils.EMPTY)}</li> * <li>{@code Pattern.compile(regex, Pattern.DOTALL).matcher(text).replaceAll(StringUtils.EMPTY)}</li> * </ul> * * <p>A {@code null} reference passed to this method is a no-op.</p> * * <pre> * StringUtils.removePattern(null, *) = null * StringUtils.removePattern("any", (String) null) = "any" * StringUtils.removePattern("A&lt;__&gt;\n&lt;__&gt;B", "&lt;.*&gt;") = "AB" * StringUtils.removePattern("ABCabc123", "[a-z]") = "ABC123" * </pre> * * @param text * the source string * @param regex * the regular expression to which this string is to be matched * @return The resulting {@code String} * @see #replacePattern(String, String, String) * @see String#replaceAll(String, String) * @see Pattern#DOTALL */
public static String removePattern(final String text, final String regex) { return replacePattern(text, regex, StringUtils.EMPTY); }

Replaces each substring of the text String that matches the given regular expression pattern with the given replacement.

This method is a null safe equivalent to:
  • pattern.matcher(text).replaceAll(replacement)

A null reference passed to this method is a no-op.

StringUtils.replaceAll(null, *, *)       = null
StringUtils.replaceAll("any", (Pattern) null, *)   = "any"
StringUtils.replaceAll("any", *, null)   = "any"
StringUtils.replaceAll("", Pattern.compile(""), "zzz")    = "zzz"
StringUtils.replaceAll("", Pattern.compile(".*"), "zzz")  = "zzz"
StringUtils.replaceAll("", Pattern.compile(".+"), "zzz")  = ""
StringUtils.replaceAll("abc", Pattern.compile(""), "ZZ")  = "ZZaZZbZZcZZ"
StringUtils.replaceAll("<__>\n<__>", Pattern.compile("<.*>"), "z")                 = "z\nz"
StringUtils.replaceAll("<__>\n<__>", Pattern.compile("<.*>", Pattern.DOTALL), "z") = "z"
StringUtils.replaceAll("<__>\n<__>", Pattern.compile("(?s)<.*>"), "z")             = "z"
StringUtils.replaceAll("ABCabc123", Pattern.compile("[a-z]"), "_")       = "ABC___123"
StringUtils.replaceAll("ABCabc123", Pattern.compile("[^A-Z0-9]+"), "_")  = "ABC_123"
StringUtils.replaceAll("ABCabc123", Pattern.compile("[^A-Z0-9]+"), "")   = "ABC123"
StringUtils.replaceAll("Lorem ipsum  dolor   sit", Pattern.compile("( +)([a-z]+)"), "_$2")  = "Lorem_ipsum_dolor_sit"
Params:
  • text – text to search and replace in, may be null
  • regex – the regular expression pattern to which this string is to be matched
  • replacement – the string to be substituted for each match
See Also:
Returns: the text with any replacements processed, null if null String input
/** * <p>Replaces each substring of the text String that matches the given regular expression pattern with the given replacement.</p> * * This method is a {@code null} safe equivalent to: * <ul> * <li>{@code pattern.matcher(text).replaceAll(replacement)}</li> * </ul> * * <p>A {@code null} reference passed to this method is a no-op.</p> * * <pre> * StringUtils.replaceAll(null, *, *) = null * StringUtils.replaceAll("any", (Pattern) null, *) = "any" * StringUtils.replaceAll("any", *, null) = "any" * StringUtils.replaceAll("", Pattern.compile(""), "zzz") = "zzz" * StringUtils.replaceAll("", Pattern.compile(".*"), "zzz") = "zzz" * StringUtils.replaceAll("", Pattern.compile(".+"), "zzz") = "" * StringUtils.replaceAll("abc", Pattern.compile(""), "ZZ") = "ZZaZZbZZcZZ" * StringUtils.replaceAll("&lt;__&gt;\n&lt;__&gt;", Pattern.compile("&lt;.*&gt;"), "z") = "z\nz" * StringUtils.replaceAll("&lt;__&gt;\n&lt;__&gt;", Pattern.compile("&lt;.*&gt;", Pattern.DOTALL), "z") = "z" * StringUtils.replaceAll("&lt;__&gt;\n&lt;__&gt;", Pattern.compile("(?s)&lt;.*&gt;"), "z") = "z" * StringUtils.replaceAll("ABCabc123", Pattern.compile("[a-z]"), "_") = "ABC___123" * StringUtils.replaceAll("ABCabc123", Pattern.compile("[^A-Z0-9]+"), "_") = "ABC_123" * StringUtils.replaceAll("ABCabc123", Pattern.compile("[^A-Z0-9]+"), "") = "ABC123" * StringUtils.replaceAll("Lorem ipsum dolor sit", Pattern.compile("( +)([a-z]+)"), "_$2") = "Lorem_ipsum_dolor_sit" * </pre> * * @param text text to search and replace in, may be null * @param regex the regular expression pattern to which this string is to be matched * @param replacement the string to be substituted for each match * @return the text with any replacements processed, * {@code null} if null String input * * @see java.util.regex.Matcher#replaceAll(String) * @see java.util.regex.Pattern */
public static String replaceAll(final String text, final Pattern regex, final String replacement) { if (text == null || regex == null || replacement == null) { return text; } return regex.matcher(text).replaceAll(replacement); }

Replaces each substring of the text String that matches the given regular expression with the given replacement.

This method is a null safe equivalent to:
  • text.replaceAll(regex, replacement)
  • Pattern.compile(regex).matcher(text).replaceAll(replacement)

A null reference passed to this method is a no-op.

Unlike in the replacePattern(String, String, String) method, the Pattern.DOTALL option is NOT automatically added. To use the DOTALL option prepend "(?s)" to the regex. DOTALL is also known as single-line mode in Perl.

StringUtils.replaceAll(null, *, *)       = null
StringUtils.replaceAll("any", (String) null, *)   = "any"
StringUtils.replaceAll("any", *, null)   = "any"
StringUtils.replaceAll("", "", "zzz")    = "zzz"
StringUtils.replaceAll("", ".*", "zzz")  = "zzz"
StringUtils.replaceAll("", ".+", "zzz")  = ""
StringUtils.replaceAll("abc", "", "ZZ")  = "ZZaZZbZZcZZ"
StringUtils.replaceAll("<__>\n<__>", "<.*>", "z")      = "z\nz"
StringUtils.replaceAll("<__>\n<__>", "(?s)<.*>", "z")  = "z"
StringUtils.replaceAll("ABCabc123", "[a-z]", "_")       = "ABC___123"
StringUtils.replaceAll("ABCabc123", "[^A-Z0-9]+", "_")  = "ABC_123"
StringUtils.replaceAll("ABCabc123", "[^A-Z0-9]+", "")   = "ABC123"
StringUtils.replaceAll("Lorem ipsum  dolor   sit", "( +)([a-z]+)", "_$2")  = "Lorem_ipsum_dolor_sit"
Params:
  • text – text to search and replace in, may be null
  • regex – the regular expression to which this string is to be matched
  • replacement – the string to be substituted for each match
Throws:
See Also:
Returns: the text with any replacements processed, null if null String input
/** * <p>Replaces each substring of the text String that matches the given regular expression * with the given replacement.</p> * * This method is a {@code null} safe equivalent to: * <ul> * <li>{@code text.replaceAll(regex, replacement)}</li> * <li>{@code Pattern.compile(regex).matcher(text).replaceAll(replacement)}</li> * </ul> * * <p>A {@code null} reference passed to this method is a no-op.</p> * * <p>Unlike in the {@link #replacePattern(String, String, String)} method, the {@link Pattern#DOTALL} option * is NOT automatically added. * To use the DOTALL option prepend {@code "(?s)"} to the regex. * DOTALL is also known as single-line mode in Perl.</p> * * <pre> * StringUtils.replaceAll(null, *, *) = null * StringUtils.replaceAll("any", (String) null, *) = "any" * StringUtils.replaceAll("any", *, null) = "any" * StringUtils.replaceAll("", "", "zzz") = "zzz" * StringUtils.replaceAll("", ".*", "zzz") = "zzz" * StringUtils.replaceAll("", ".+", "zzz") = "" * StringUtils.replaceAll("abc", "", "ZZ") = "ZZaZZbZZcZZ" * StringUtils.replaceAll("&lt;__&gt;\n&lt;__&gt;", "&lt;.*&gt;", "z") = "z\nz" * StringUtils.replaceAll("&lt;__&gt;\n&lt;__&gt;", "(?s)&lt;.*&gt;", "z") = "z" * StringUtils.replaceAll("ABCabc123", "[a-z]", "_") = "ABC___123" * StringUtils.replaceAll("ABCabc123", "[^A-Z0-9]+", "_") = "ABC_123" * StringUtils.replaceAll("ABCabc123", "[^A-Z0-9]+", "") = "ABC123" * StringUtils.replaceAll("Lorem ipsum dolor sit", "( +)([a-z]+)", "_$2") = "Lorem_ipsum_dolor_sit" * </pre> * * @param text text to search and replace in, may be null * @param regex the regular expression to which this string is to be matched * @param replacement the string to be substituted for each match * @return the text with any replacements processed, * {@code null} if null String input * * @throws java.util.regex.PatternSyntaxException * if the regular expression's syntax is invalid * * @see #replacePattern(String, String, String) * @see String#replaceAll(String, String) * @see java.util.regex.Pattern * @see java.util.regex.Pattern#DOTALL */
public static String replaceAll(final String text, final String regex, final String replacement) { if (text == null || regex == null || replacement == null) { return text; } return text.replaceAll(regex, replacement); }

Replaces the first substring of the text string that matches the given regular expression pattern with the given replacement.

This method is a null safe equivalent to:
  • pattern.matcher(text).replaceFirst(replacement)

A null reference passed to this method is a no-op.

StringUtils.replaceFirst(null, *, *)       = null
StringUtils.replaceFirst("any", (Pattern) null, *)   = "any"
StringUtils.replaceFirst("any", *, null)   = "any"
StringUtils.replaceFirst("", Pattern.compile(""), "zzz")    = "zzz"
StringUtils.replaceFirst("", Pattern.compile(".*"), "zzz")  = "zzz"
StringUtils.replaceFirst("", Pattern.compile(".+"), "zzz")  = ""
StringUtils.replaceFirst("abc", Pattern.compile(""), "ZZ")  = "ZZabc"
StringUtils.replaceFirst("<__>\n<__>", Pattern.compile("<.*>"), "z")      = "z\n<__>"
StringUtils.replaceFirst("<__>\n<__>", Pattern.compile("(?s)<.*>"), "z")  = "z"
StringUtils.replaceFirst("ABCabc123", Pattern.compile("[a-z]"), "_")          = "ABC_bc123"
StringUtils.replaceFirst("ABCabc123abc", Pattern.compile("[^A-Z0-9]+"), "_")  = "ABC_123abc"
StringUtils.replaceFirst("ABCabc123abc", Pattern.compile("[^A-Z0-9]+"), "")   = "ABC123abc"
StringUtils.replaceFirst("Lorem ipsum  dolor   sit", Pattern.compile("( +)([a-z]+)"), "_$2")  = "Lorem_ipsum  dolor   sit"
Params:
  • text – text to search and replace in, may be null
  • regex – the regular expression pattern to which this string is to be matched
  • replacement – the string to be substituted for the first match
See Also:
Returns: the text with the first replacement processed, null if null String input
/** * <p>Replaces the first substring of the text string that matches the given regular expression pattern * with the given replacement.</p> * * This method is a {@code null} safe equivalent to: * <ul> * <li>{@code pattern.matcher(text).replaceFirst(replacement)}</li> * </ul> * * <p>A {@code null} reference passed to this method is a no-op.</p> * * <pre> * StringUtils.replaceFirst(null, *, *) = null * StringUtils.replaceFirst("any", (Pattern) null, *) = "any" * StringUtils.replaceFirst("any", *, null) = "any" * StringUtils.replaceFirst("", Pattern.compile(""), "zzz") = "zzz" * StringUtils.replaceFirst("", Pattern.compile(".*"), "zzz") = "zzz" * StringUtils.replaceFirst("", Pattern.compile(".+"), "zzz") = "" * StringUtils.replaceFirst("abc", Pattern.compile(""), "ZZ") = "ZZabc" * StringUtils.replaceFirst("&lt;__&gt;\n&lt;__&gt;", Pattern.compile("&lt;.*&gt;"), "z") = "z\n&lt;__&gt;" * StringUtils.replaceFirst("&lt;__&gt;\n&lt;__&gt;", Pattern.compile("(?s)&lt;.*&gt;"), "z") = "z" * StringUtils.replaceFirst("ABCabc123", Pattern.compile("[a-z]"), "_") = "ABC_bc123" * StringUtils.replaceFirst("ABCabc123abc", Pattern.compile("[^A-Z0-9]+"), "_") = "ABC_123abc" * StringUtils.replaceFirst("ABCabc123abc", Pattern.compile("[^A-Z0-9]+"), "") = "ABC123abc" * StringUtils.replaceFirst("Lorem ipsum dolor sit", Pattern.compile("( +)([a-z]+)"), "_$2") = "Lorem_ipsum dolor sit" * </pre> * * @param text text to search and replace in, may be null * @param regex the regular expression pattern to which this string is to be matched * @param replacement the string to be substituted for the first match * @return the text with the first replacement processed, * {@code null} if null String input * * @see java.util.regex.Matcher#replaceFirst(String) * @see java.util.regex.Pattern */
public static String replaceFirst(final String text, final Pattern regex, final String replacement) { if (text == null || regex == null|| replacement == null ) { return text; } return regex.matcher(text).replaceFirst(replacement); }

Replaces the first substring of the text string that matches the given regular expression with the given replacement.

This method is a null safe equivalent to:
  • text.replaceFirst(regex, replacement)
  • Pattern.compile(regex).matcher(text).replaceFirst(replacement)

A null reference passed to this method is a no-op.

The Pattern.DOTALL option is NOT automatically added. To use the DOTALL option prepend "(?s)" to the regex. DOTALL is also known as single-line mode in Perl.

StringUtils.replaceFirst(null, *, *)       = null
StringUtils.replaceFirst("any", (String) null, *)   = "any"
StringUtils.replaceFirst("any", *, null)   = "any"
StringUtils.replaceFirst("", "", "zzz")    = "zzz"
StringUtils.replaceFirst("", ".*", "zzz")  = "zzz"
StringUtils.replaceFirst("", ".+", "zzz")  = ""
StringUtils.replaceFirst("abc", "", "ZZ")  = "ZZabc"
StringUtils.replaceFirst("<__>\n<__>", "<.*>", "z")      = "z\n<__>"
StringUtils.replaceFirst("<__>\n<__>", "(?s)<.*>", "z")  = "z"
StringUtils.replaceFirst("ABCabc123", "[a-z]", "_")          = "ABC_bc123"
StringUtils.replaceFirst("ABCabc123abc", "[^A-Z0-9]+", "_")  = "ABC_123abc"
StringUtils.replaceFirst("ABCabc123abc", "[^A-Z0-9]+", "")   = "ABC123abc"
StringUtils.replaceFirst("Lorem ipsum  dolor   sit", "( +)([a-z]+)", "_$2")  = "Lorem_ipsum  dolor   sit"
Params:
  • text – text to search and replace in, may be null
  • regex – the regular expression to which this string is to be matched
  • replacement – the string to be substituted for the first match
Throws:
See Also:
Returns: the text with the first replacement processed, null if null String input
/** * <p>Replaces the first substring of the text string that matches the given regular expression * with the given replacement.</p> * * This method is a {@code null} safe equivalent to: * <ul> * <li>{@code text.replaceFirst(regex, replacement)}</li> * <li>{@code Pattern.compile(regex).matcher(text).replaceFirst(replacement)}</li> * </ul> * * <p>A {@code null} reference passed to this method is a no-op.</p> * * <p>The {@link Pattern#DOTALL} option is NOT automatically added. * To use the DOTALL option prepend {@code "(?s)"} to the regex. * DOTALL is also known as single-line mode in Perl.</p> * * <pre> * StringUtils.replaceFirst(null, *, *) = null * StringUtils.replaceFirst("any", (String) null, *) = "any" * StringUtils.replaceFirst("any", *, null) = "any" * StringUtils.replaceFirst("", "", "zzz") = "zzz" * StringUtils.replaceFirst("", ".*", "zzz") = "zzz" * StringUtils.replaceFirst("", ".+", "zzz") = "" * StringUtils.replaceFirst("abc", "", "ZZ") = "ZZabc" * StringUtils.replaceFirst("&lt;__&gt;\n&lt;__&gt;", "&lt;.*&gt;", "z") = "z\n&lt;__&gt;" * StringUtils.replaceFirst("&lt;__&gt;\n&lt;__&gt;", "(?s)&lt;.*&gt;", "z") = "z" * StringUtils.replaceFirst("ABCabc123", "[a-z]", "_") = "ABC_bc123" * StringUtils.replaceFirst("ABCabc123abc", "[^A-Z0-9]+", "_") = "ABC_123abc" * StringUtils.replaceFirst("ABCabc123abc", "[^A-Z0-9]+", "") = "ABC123abc" * StringUtils.replaceFirst("Lorem ipsum dolor sit", "( +)([a-z]+)", "_$2") = "Lorem_ipsum dolor sit" * </pre> * * @param text text to search and replace in, may be null * @param regex the regular expression to which this string is to be matched * @param replacement the string to be substituted for the first match * @return the text with the first replacement processed, * {@code null} if null String input * * @throws java.util.regex.PatternSyntaxException * if the regular expression's syntax is invalid * * @see String#replaceFirst(String, String) * @see java.util.regex.Pattern * @see java.util.regex.Pattern#DOTALL */
public static String replaceFirst(final String text, final String regex, final String replacement) { if (text == null || regex == null|| replacement == null ) { return text; } return text.replaceFirst(regex, replacement); }

Replaces each substring of the source String that matches the given regular expression with the given replacement using the Pattern.DOTALL option. DOTALL is also known as single-line mode in Perl.

This call is a null safe equivalent to:
  • text.replaceAll(&quot;(?s)&quot; + regex, replacement)
  • Pattern.compile(regex, Pattern.DOTALL).matcher(text).replaceAll(replacement)

A null reference passed to this method is a no-op.

StringUtils.replacePattern(null, *, *)       = null
StringUtils.replacePattern("any", (String) null, *)   = "any"
StringUtils.replacePattern("any", *, null)   = "any"
StringUtils.replacePattern("", "", "zzz")    = "zzz"
StringUtils.replacePattern("", ".*", "zzz")  = "zzz"
StringUtils.replacePattern("", ".+", "zzz")  = ""
StringUtils.replacePattern("<__>\n<__>", "<.*>", "z")       = "z"
StringUtils.replacePattern("ABCabc123", "[a-z]", "_")       = "ABC___123"
StringUtils.replacePattern("ABCabc123", "[^A-Z0-9]+", "_")  = "ABC_123"
StringUtils.replacePattern("ABCabc123", "[^A-Z0-9]+", "")   = "ABC123"
StringUtils.replacePattern("Lorem ipsum  dolor   sit", "( +)([a-z]+)", "_$2")  = "Lorem_ipsum_dolor_sit"
Params:
  • text – the source string
  • regex – the regular expression to which this string is to be matched
  • replacement – the string to be substituted for each match
See Also:
Returns:The resulting String
/** * <p>Replaces each substring of the source String that matches the given regular expression with the given * replacement using the {@link Pattern#DOTALL} option. DOTALL is also known as single-line mode in Perl.</p> * * This call is a {@code null} safe equivalent to: * <ul> * <li>{@code text.replaceAll(&quot;(?s)&quot; + regex, replacement)}</li> * <li>{@code Pattern.compile(regex, Pattern.DOTALL).matcher(text).replaceAll(replacement)}</li> * </ul> * * <p>A {@code null} reference passed to this method is a no-op.</p> * * <pre> * StringUtils.replacePattern(null, *, *) = null * StringUtils.replacePattern("any", (String) null, *) = "any" * StringUtils.replacePattern("any", *, null) = "any" * StringUtils.replacePattern("", "", "zzz") = "zzz" * StringUtils.replacePattern("", ".*", "zzz") = "zzz" * StringUtils.replacePattern("", ".+", "zzz") = "" * StringUtils.replacePattern("&lt;__&gt;\n&lt;__&gt;", "&lt;.*&gt;", "z") = "z" * StringUtils.replacePattern("ABCabc123", "[a-z]", "_") = "ABC___123" * StringUtils.replacePattern("ABCabc123", "[^A-Z0-9]+", "_") = "ABC_123" * StringUtils.replacePattern("ABCabc123", "[^A-Z0-9]+", "") = "ABC123" * StringUtils.replacePattern("Lorem ipsum dolor sit", "( +)([a-z]+)", "_$2") = "Lorem_ipsum_dolor_sit" * </pre> * * @param text * the source string * @param regex * the regular expression to which this string is to be matched * @param replacement * the string to be substituted for each match * @return The resulting {@code String} * @see #replaceAll(String, String, String) * @see String#replaceAll(String, String) * @see Pattern#DOTALL */
public static String replacePattern(final String text, final String regex, final String replacement) { if (text == null || regex == null || replacement == null) { return text; } return Pattern.compile(regex, Pattern.DOTALL).matcher(text).replaceAll(replacement); } }