net.hasor.db.jdbc.mapper.SingleColumnRowMapper Maven / Gradle / Ivy
/*
* Copyright 2002-2009 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 net.hasor.db.jdbc.mapper;
import net.hasor.db.types.TypeHandlerRegistry;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
/**
*
* @version : 2014年5月23日
* @author 赵永春 ([email protected])
*/
public class SingleColumnRowMapper extends AbstractRowMapper {
private Class requiredType;
/**
* Create a new SingleColumnRowMapper.
* @param requiredType the type that each result object is expected to match
*/
public SingleColumnRowMapper(Class requiredType) {
this(requiredType, TypeHandlerRegistry.DEFAULT);
}
/**
* Create a new SingleColumnRowMapper.
* @param requiredType the type that each result object is expected to match
*/
public SingleColumnRowMapper(Class requiredType, TypeHandlerRegistry typeHandler) {
super(typeHandler);
this.requiredType = requiredType;
}
/** Set the type that each result object is expected to match. If not specified, the column value will be exposed as returned by the JDBC driver. */
public void setRequiredType(final Class requiredType) {
this.requiredType = requiredType;
}
/** 将当前行的第一列的值转换为指定的类型。*/
@Override
public T mapRow(final ResultSet rs, final int rowNum) throws SQLException {
ResultSetMetaData rsmd = rs.getMetaData();
int nrOfColumns = rsmd.getColumnCount();
if (nrOfColumns != 1) {
throw new SQLException("Incorrect column count: expected 1, actual " + nrOfColumns);
}
return (T) getResultSetValue(rs, 1, this.requiredType);
}
}