（1）創建一個接口
package com.min.dao;public interface UserDao {public void save(String uname, String pwd);}
（2）創建一個實現類將用戶信息保存到mysql數據庫中
package com.min.dao.impl;import com.min.dao.UserDao;public class UserDaoMysqlImpl implements UserDao {@Overridepublic void save(String uname, String pwd) {System.out.println("----------UserDaoMysqlImpl----------------");}}
（3）創建一個實現類將用戶信息保存到oracle數據庫中
package com.min.dao.impl;import com.min.dao.UserDao;public class UserDaoOracleImpl implements UserDao{@Overridepublic void save(String uname, String pwd) {System.out.println("----------UserDaoOracleImpl----------------");}}
（4）創建一個管理類，將接口對象作為其屬性
package com.min.manager;import com.min.dao.UserDao;public class UserManager {private UserDao userDao; ／／將接口對象作為屬性public void save (String uname, String pwd) {userDao.save(uname, pwd);}public UserDao getUserDao() {return userDao;}public void setUserDao(UserDao userDao) {this.userDao = userDao;}}
（5）在Spring配置文件applicationContext.xml將javaBean由Spring管理?
<?xml version="1.0" encoding="UTF-8"?> <beansxmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns:p="http://www.springframework.org/schema/p"xmlns:aop="http://www.springframework.org/schema/aop"xmlns:tx="http://www.springframework.org/schema/tx"xmlns:context="http://www.springframework.org/schema/context"xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsdhttp://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.1.xsdhttp://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.1.xsdhttp://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd"><bean id="hellword" class="com.min.Hellword"><property name="message" value="heel"></property></bean><bean id="mysqlimpl" class="com.min.dao.impl.UserDaoMysqlImpl"></bean><bean id="oracleimpl" class="com.min.dao.impl.UserDaoOracleImpl"></bean>
<!-- manager的userDao屬性依賴注入Spring來注入，可以在程序中無需修改代碼，就可以注入不同實例，本例中向mysql保存數據就注入mysqlimpl，如果后來向Oracle中保存數據只需修改注入實例--><bean id="usermanager" class="com.min.manager.UserManager"><property name="userDao" ref="mysqlimpl"></property></bean></beans>
（6）編寫測試類
package com.min.test;import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext;import com.min.manager.UserManager;public class Test {public static void main(String[] args) {ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");UserManager manager = (UserManager)context.getBean("usermanager");manager.save("user", "pwd ");} }
執行結果
四月 21, 2019 10:46:19 上午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@5f4da5c3: startup date ; root of context hierarchy
四月 21, 2019 10:46:19 上午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from class path resource [applicationContext.xml]
----------UserDaoMysqlImpl----------------pwd ?
