07 Spring JDBC Support Spring对于JDBC的支持

   本文描述的是Spring对于JDBC的支持，主要用示例去说明问题。需要的环境是一个你喜欢的ide。我用的是Myeclipse7.5。数据库是mysql5.0.另外您可能还需要一个mysql的jdbc驱动（这个网上到处都是）下面开始。

一、直接使用JDBC会产生的问题

    直接使用jdbc的话，您会写很多模版性的代码。下面举例说明：

    1、创建数据库：CREATE TABLE VEHICLE ( VEHICLE_NO VARCHAR(10) NOT NULL, COLOR VARCHAR(10), WHEEL INT, SEAT INT, PRIMARY KEY (VEHICLE_NO));

    2、编写实体类：package com.oletech.spring;/** * Vehicle类 * * @version 1.0 2010-1-26 * @author wangtm * */public class Vehicle {private String vehicleNo;private String color;private int wheel;private int seat;public Vehicle() {}public Vehicle(String vehicleNo, String color, int wheel, int seat) {this.vehicleNo = vehicleNo;this.color = color;this.wheel = wheel;this.seat = seat;}public String getVehicleNo() {return vehicleNo;}public void setVehicleNo(String vehicleNo) {this.vehicleNo = vehicleNo;}public String getColor() {return color;}public void setColor(String color) {this.color = color;}public int getWheel() {return wheel;}public void setWheel(int wheel) {this.wheel = wheel;}public int getSeat() {return seat;}public void setSeat(int seat) {this.seat = seat;}}

    3、编写dao接口：package com.oletech.spring;/** * * @version 1.0 2010-1-26 * @author wangtm * */public interface VehicleDao {public void insert(Vehicle vehicle);public void update(Vehicle vehicle);public void delete(Vehicle vehicle);public Vehicle findByVehicleNo(String vehicleNo);}

    4、实现接口：  package com.oletech.spring;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import javax.sql.DataSource;/** * Spring JDBC的示例，本例说明直接使用JDBC会产生的问题 * * @version 1.0 2010-1-26 * @author wangtm * */public class JdbcVehicleDao implements VehicleDao {private DataSource dataSource;public void setDataSource(DataSource dataSource){this.dataSource = dataSource;}@Overridepublic void insert(Vehicle vehicle) {String sql = "INSERT INTO vehicle (vehicle_no, color, wheel, seat) " + "VALUES(?, ?, ?, ?)";Connection conn = null;try {conn = dataSource.getConnection();PreparedStatement ps = conn.prepareStatement(sql);ps.setString(1, vehicle.getVehicleNo());ps.setString(2, vehicle.getColor());ps.setInt(3, vehicle.getWheel());ps.setInt(4, vehicle.getSeat());ps.executeUpdate();ps.close();} catch (SQLException e) {throw new RuntimeException(e);}finally{/* * finally里的code 就是模版性的代码了。 * 很啰嗦！都是重复的，没必要去每次都写 */if(conn != null){try{conn.close();}catch(SQLException e){}}}}@Overridepublic Vehicle findByVehicleNo(String vehicleNo) {String sql = "SELECT * FROM VEHICLE WHERE VEHICLE_NO = ?";Connection conn = null;try {conn = dataSource.getConnection();PreparedStatement ps = conn.prepareStatement(sql);ps.setString(1, vehicleNo);Vehicle vehicle = null;ResultSet rs = ps.executeQuery();if(rs.next()){vehicle = new Vehicle(rs.getString("VEHICLE_NO"),rs.getString("COLOR"), rs.getInt("WHEEL"),rs.getInt("SEAT"));}else{throw new RuntimeException("数据库中没有相应记录");}rs.close();ps.close();return vehicle;} catch (SQLException e) {throw new RuntimeException(e);}finally{/* * finally里的code 就是模版性的代码了。 * 很啰嗦！都是重复的，没必要去每次都写 */if(conn != null){try{conn.close();}catch(SQLException e){}}}}@Overridepublic void delete(Vehicle vehicle) {//和insert、find类似所以没有实现 }@Overridepublic void update(Vehicle vehicle) {//和insert、find类似所以没有实现 }}

    5、Spring配置文件（beans.xml）：<beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:jee="http://www.springframework.org/schema/jee"xsi:schemaLocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans-2.0.xsdhttp://www.springframework.org/schema/jeehttp://www.springframework.org/schema/jee/spring-jee-2.0.xsd"><bean id="vehicleDao" class="com.oletech.spring.JdbcVehicleDao"><property name="dataSource" ref="dataSource" /></bean><!-- dbcp 数据源 (我选用这个数据源。您还可以根据您具体的境况选择别的数据，例如下面的两个仅供参考)--><bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"><property name="driverClassName" value="com.mysql.jdbc.Driver" /><property name="url" value="jdbc:mysql:///vehicle" /><!-- 这里改成您的数据库url --><property name="username" value="root" /><property name="password" value="mysql" /><property name="initialSize" value="2" /><property name="maxActive" value="3" /></bean><!-- spring自带的，多用于测试<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource"><property name="driverClassName" value="com.mysql.jdbc.Driver" /><property name="url" value="jdbc:mysql:///vehicle" /><property name="username" value="root" /><property name="password" value="mysql" /></bean>--><!-- javaEE 级开发jndi 数据源<bean id="dataSource" class="org.springframework.jndi.JndiObjectFactoryBean"> <property name="jndiName" value="jdbc/VehicleDS" /> </bean><jee:jndi-lookup id="dataSource" jndi-name="jdbc/VehicleDS" />--></beans>

    6、运行测试：package com.oletech.spring;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;public class Main {public static void main(String[] args) {ApplicationContext context = new ClassPathXmlApplicationContext("com/oletech/spring/beans.xml");VehicleDao vehicleDao = (VehicleDao) context.getBean("vehicleDao");Vehicle vehicle = new Vehicle("TEM0001", "Red", 4, 4);vehicleDao.insert(vehicle);vehicle = vehicleDao.findByVehicleNo("TEM0001");System.out.println("Vehicle No: " + vehicle.getVehicleNo());System.out.println("Color: " + vehicle.getColor());System.out.println("Wheel: " + vehicle.getWheel());System.out.println("Seat: " + vehicle.getSeat());}}

   以上代码都要放在同一个包下，即com.oletech.spring包下。下面再来看看Spring会为我带来多少好处。

    待续..... 2010-01-26 15:02:58