使用set方法实现DI依赖注入

通过写set方法,注入set方法,达到”从spring容器获取的service bean内部包含dao对象”的目的

[开发步骤]

- dao实现类中写set方法

- xml中配置set方法

- 测试类中无需改动,此时从spring容器获取service对象默认包含dao对象

MODULE:jSpringAbc

com.it.service包

UserService接口

package com.it.service;

public interface UserService {

    void save();

}

com.it.service.impl包

UserServiceImpl类

package com.it.service.impl;

import com.it.dao.UserDao;

import com.it.service.UserService;

public class UserServiceImpl implements UserService {

    private UserDao userDao;

    public void setUserDao(UserDao userDao) {

        this.userDao = userDao;

    }

    @Override

    public void save() {

        userDao.save();

    }

}

resources包

applicationContext.xml文件

       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

       xmlns:context="http://www.springframework.org/schema/context"

       xsi:schemaLocation="http://www.springframework.org/schema/beans

       http://www.springframework.org/schema/beans/spring-beans.xsd

       http://www.springframework.org/schema/context

       http://www.springframework.org/schema/context/spring-context.xsd">

    

    

        

    

com.it.test包

SetDependencyInjectDemo类

package com.it.test;

import com.it.service.UserService;

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class SetDependencyInjectDemo {

    public static void main(String[] args) {

        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");

        UserService userService=(UserService)applicationContext.getBean("userService");

        userService.save();

    }

}