依赖注入

1，接口类

package com.songyan.demo1;

public interface UserDao {
public void say();
}

package com.songyan.demo1;

public interface UserService {
public void say();
}

2，实现类

package com.songyan.demo1;


public class UserDaoImpl implements UserDao{
    public void say()
    {
        System.out.println("UsdeDao say helloWord");
    }

}

package com.songyan.demo1;


public class UserServiceImpl implements UserService{
private UserDao userDao;
public void setUserDao(UserDao userDao)
{
    this.userDao=userDao;
}
public void say()
{
    this.userDao.say();
    System.out.println("hello");
}
}

3，配置文档

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd">

<bean id="userDao" class="com.songyan.demo1.UserDaoImpl" ></bean>
<bean id="userService" class="com.songyan.demo1.UserServiceImpl">
<property name="userDao" ref="userDao"></property></bean>
</beans>

3，测试类

package com.songyan.demo1;

import javax.xml.registry.infomodel.User;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Test {
public static void main(String[] args) {
	//初始化容器，加载xml
	ApplicationContext application =new ClassPathXmlApplicationContext("applicationContext.xml");
	//通过容器获取javabean对象实例
	UserDao userDao=(UserDao)application.getBean("userDao");
	//调用实例的方法
	userDao.say();
	//通过容器获取UserService对象
	UserService userService=(UserService)application.getBean("userService");
	userService.say();
}
}