query for a List<String> using DBUtils

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有时我们只对某张表中的某一列比较感兴趣，例如我们想查询学生表中年龄<25岁的学生姓名，返回结果应是 List<String>对象，这个时候ColumnListHandler 就派上用场了，示例代码如下：

package com.ricky.java.junit;import java.sql.SQLException;import java.util.List;import javax.sql.DataSource;import org.apache.commons.dbutils.handlers.ColumnListHandler;import com.ricky.java.common.dao.AbstractDAO;import com.ricky.java.common.db.DataSourceManager;public class StudentDAO extends AbstractDAO {public List<String> queryNameList() throws SQLException{return qr.query("SELECT name from dict_student where age<25", new ColumnListHandler<String>(1));}@Overrideprotected DataSource getDataSource() {return DataSourceManager.getInstance().getDataSource();}}

AbstractDAO.java

package com.ricky.java.common.dao;import javax.sql.DataSource;import org.apache.commons.dbutils.QueryRunner;import org.apache.log4j.Logger;/** * 实现通用数据库CRUD操作 接口基类 * @author Bingbing Feng *  * @version 2014-10-13 14:30 V1.1 * */public abstract class AbstractDAO {protected Logger mLogger = Logger.getLogger("devLog");protected QueryRunner qr = new QueryRunner(getDataSource());//get DataSourceprotected abstract DataSource getDataSource();}

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