Spring中的依赖原理

代码描述依赖过程

Dao层代码

package com.cloud.reply;public interface UserDao {void printInfo();}

实现层代码

package com.cloud.reply;public class UserDaoImpl implements UserDao{private String jdbcUrl;private String driverClass;private String username;private String password;@Overridepublic void printInfo() {System.out.println("jdbcUrl"+jdbcUrl);System.out.println("driverClass"+driverClass);System.out.println("username"+username);System.out.println("password"+password);}public String getJdbcUrl() {return jdbcUrl;}public void setJdbcUrl(String jdbcUrl) {this.jdbcUrl = jdbcUrl;}public String getDriverClass() {return driverClass;}public void setDriverClass(String driverClass) {this.driverClass = driverClass;}public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}}

服务层代码

package com.cloud.reply;public class UserDaoServiceImpl {private UserDao userDao;public UserDao getUserDao() {return userDao;}public void setUserDao(UserDao userDao) {this.userDao = userDao;}}

配置文件

<span style="white-space:pre"></span><!-- 配置一个userdao --><bean id="userDao" class="com.cloud.reply.UserDaoImpl"><property name="jdbcUrl" value="jdbc:mysql:///test"/><property name="driverClass" value="com.mysql.jdbc.Driver"/><property name="username" value="root"/><property name="password" value="root"/></bean><!-- 配置UserService对象，依赖UserDao对象 --><bean id="userServiceImpl" class="com.cloud.reply.UserDaoServiceImpl"><property name="userDao" ref="userDao"></property></bean>

测试代码

package com.cloud.reply;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;public class MyTest {public static void main(String[] args) {ApplicationContext ac= new ClassPathXmlApplicationContext("applicationContext.xml");UserDao userDao = (UserDao) ac.getBean("userDao");UserDaoServiceImpl userServiceImpl = (UserDaoServiceImpl) ac.getBean("userServiceImpl");System.out.println(userDao);System.out.println(userServiceImpl.getUserDao());userDao.printInfo();}}