•commons-dbutils 是 Apache 组织提供的一个开源 JDBC工具类库，它是对JDBC的简单封装。学习成本极低。而且使用dbutils能极大简化jdbc编码的工作量，同一时候也不会影响程序的性能。

•API介绍：

–org.apache.commons.dbutils.QueryRunner

–org.apache.commons.dbutils.ResultSetHandler

–工具类

•org.apache.commons.dbutils.DbUtils。

QueryRunner类有两类主要方法:

query() : 用于查询数据

update() : 用于增删改

ResultSetHandler接口用与将查询到的数据按要求转换为还有一种格式。

-------------------------------------------------下面为详细的Demo--------------------------------------------------------------

QueryRunner.update()

<span style="font-size:14px;">	/**

	 * 測试 QueryRunner 类的 update 方法

	 * 该方法可用于 INSERT, UPDATE 和 DELETE

	 */

	@Test

	public void testQueryRunnerUpdate() {

		//1. 创建 QueryRunner 的实现类

		QueryRunner queryRunner = new QueryRunner();

		String sql = "DELETE FROM customers " +

				"WHERE id IN (?,?)";

		Connection connection = null;

		try {

			connection = JDBCTools.getConnection();

			//2. 使用其 update 方法

			queryRunner.update(connection,

					sql, 12, 13);

		} catch (Exception e) {

			e.printStackTrace();

		} finally{

			JDBCTools.releaseDB(null, null, connection);

		}

	}</span>

BeanHandler:把结果集的第一条记录转为创建BeanHandler对象时传入的Class參数相应的对象.

<span style="font-family:SimSun;font-size:14px;"><span style="font-size:14px;font-weight: normal;">public void testBeanHandler() {

		QueryRunner queryRunner = new QueryRunner();

		Connection conn = null;

		try {

			conn = JDBCTools.getConnection();

			String sql = "SELECT id, name customerName, email, birth "

					+ "FROM customers WHERE id>=?";

			Customer customer = queryRunner.query(conn, sql, new BeanHandler(

					Customer.class), 5);

			System.out.println(customer);

		} catch (Exception e) {

			e.printStackTrace();

		} finally {

			JDBCTools.releaseDB(null, null, conn);

		}

	}</span></span>

BeanListHandler:把结果集转为一个List,该List不为null,但可能为空集合(即size()方法返回0)

<span style="font-family:SimSun;font-size:14px;">public void testBeanListHandler(){

		String sql = "SELECT id, name customerName, email, birth " +

				"FROM customers";

		QueryRunner queryRunner = new QueryRunner();

		Connection conn = null;

		try {

			conn = JDBCTools.getConnection();

			Object object = queryRunner.query(conn, sql,

					new BeanListHandler<>(Customer.class)); 			

			System.out.println(object);

		} catch (Exception e) {

			e.printStackTrace();

		} finally{

			JDBCTools.releaseDB(null, null, conn);

		}

	}</span>

MapHandler:返回SQL语句相应的第一条记录相应的Map对象.键:SQL查询的列名(不是列的别名),值:列的值.

<span style="font-family:SimSun;font-size:14px;"><span style="font-size:14px;font-weight: normal;">public void testMapHandler(){

		Connection connection = null;

		QueryRunner queryRunner = new QueryRunner();

		String sql = "SELECT id, name customerName, email, birth " +

				"FROM customers WHERE id = ?

";

		try {

			connection = JDBCTools.getConnection();

			Map<String, Object> map = queryRunner.query(connection,

					sql, new MapHandler(), 4);

			System.out.println(map);

		} catch (Exception e) {

			e.printStackTrace();

		} finally{

			JDBCTools.releaseDB(null, null, connection);

		}

	}</span></span>

MapLiatHandler:将结果转化为一个Map的List. MapLiatHandler:返回的多条记录相应的Map的集合.

<span style="font-family:SimSun;font-size:14px;font-weight: normal;">public void testMapListHandler(){

		Connection connection = null;

		QueryRunner queryRunner = new QueryRunner();

		String sql = "SELECT id, name, email, birth " +

				"FROM customers";

		try {

			connection = JDBCTools.getConnection();

			List<Map<String, Object>> mapList = queryRunner.query(connection,

					sql, new MapListHandler());

			System.out.println(mapList);

		} catch (Exception e) {

			e.printStackTrace();

		} finally{

			JDBCTools.releaseDB(null, null, connection);

		}

	}</span>

ScalarHandler:把结果集转为一个数值(能够是随意类型)返回

<span style="font-family:SimSun;">public void testScalarHandler(){

		Connection connection = null;

		QueryRunner queryRunner = new QueryRunner();

		String sql = "SELECT name FROM customers " +

				"WHERE id = ?";

		try {

			connection = JDBCTools.getConnection();

			Object count = queryRunner.query(connection, sql,

					new ScalarHandler(), 6);

			System.out.println(count);

		} catch (Exception e) {

			e.printStackTrace();

		} finally{

			JDBCTools.releaseDB(null, null, connection);

		}

	}</span>