/*
* Copyright 2002-2018 the original author or authors.
*
* Licensed 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.springframework.jdbc.core;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.Map;
import org.springframework.jdbc.support.JdbcUtils;
import org.springframework.lang.Nullable;
import org.springframework.util.LinkedCaseInsensitiveMap;
RowMapper
implementation that creates a java.util.Map
for each row, representing all columns as key-value pairs: one entry for each column, with the column name as key. The Map implementation to use and the key to use for each column in the column Map can be customized through overriding createColumnMap
and getColumnKey
, respectively.
Note: By default, ColumnMapRowMapper will try to build a linked Map
with case-insensitive keys, to preserve column order as well as allow any
casing to be used for column names. This requires Commons Collections on the
classpath (which will be autodetected). Else, the fallback is a standard linked
HashMap, which will still preserve column order but requires the application
to specify the column names in the same casing as exposed by the driver.
Author: Juergen Hoeller See Also: Since: 1.2
/**
* {@link RowMapper} implementation that creates a {@code java.util.Map}
* for each row, representing all columns as key-value pairs: one
* entry for each column, with the column name as key.
*
* <p>The Map implementation to use and the key to use for each column
* in the column Map can be customized through overriding
* {@link #createColumnMap} and {@link #getColumnKey}, respectively.
*
* <p><b>Note:</b> By default, ColumnMapRowMapper will try to build a linked Map
* with case-insensitive keys, to preserve column order as well as allow any
* casing to be used for column names. This requires Commons Collections on the
* classpath (which will be autodetected). Else, the fallback is a standard linked
* HashMap, which will still preserve column order but requires the application
* to specify the column names in the same casing as exposed by the driver.
*
* @author Juergen Hoeller
* @since 1.2
* @see JdbcTemplate#queryForList(String)
* @see JdbcTemplate#queryForMap(String)
*/
public class ColumnMapRowMapper implements RowMapper<Map<String, Object>> {
@Override
public Map<String, Object> mapRow(ResultSet rs, int rowNum) throws SQLException {
ResultSetMetaData rsmd = rs.getMetaData();
int columnCount = rsmd.getColumnCount();
Map<String, Object> mapOfColumnValues = createColumnMap(columnCount);
for (int i = 1; i <= columnCount; i++) {
String column = JdbcUtils.lookupColumnName(rsmd, i);
mapOfColumnValues.putIfAbsent(getColumnKey(column), getColumnValue(rs, i));
}
return mapOfColumnValues;
}
Create a Map instance to be used as column map.
By default, a linked case-insensitive Map will be created.
Params: - columnCount – the column count, to be used as initial
capacity for the Map
See Also: Returns: the new Map instance
/**
* Create a Map instance to be used as column map.
* <p>By default, a linked case-insensitive Map will be created.
* @param columnCount the column count, to be used as initial
* capacity for the Map
* @return the new Map instance
* @see org.springframework.util.LinkedCaseInsensitiveMap
*/
protected Map<String, Object> createColumnMap(int columnCount) {
return new LinkedCaseInsensitiveMap<>(columnCount);
}
Determine the key to use for the given column in the column Map.
Params: - columnName – the column name as returned by the ResultSet
See Also: Returns: the column key to use
/**
* Determine the key to use for the given column in the column Map.
* @param columnName the column name as returned by the ResultSet
* @return the column key to use
* @see java.sql.ResultSetMetaData#getColumnName
*/
protected String getColumnKey(String columnName) {
return columnName;
}
Retrieve a JDBC object value for the specified column.
The default implementation uses the getObject
method. Additionally, this implementation includes a "hack" to get around Oracle returning a non standard object for their TIMESTAMP datatype.
Params: - rs – is the ResultSet holding the data
- index – is the column index
See Also: Returns: the Object returned
/**
* Retrieve a JDBC object value for the specified column.
* <p>The default implementation uses the {@code getObject} method.
* Additionally, this implementation includes a "hack" to get around Oracle
* returning a non standard object for their TIMESTAMP datatype.
* @param rs is the ResultSet holding the data
* @param index is the column index
* @return the Object returned
* @see org.springframework.jdbc.support.JdbcUtils#getResultSetValue
*/
@Nullable
protected Object getColumnValue(ResultSet rs, int index) throws SQLException {
return JdbcUtils.getResultSetValue(rs, index);
}
}