spring-04-对象注入

对象注入

一个对象

package com.spring.service;
public class MessageService {
    public void deleteById(Long id) {
        System.out.println("已删除id=" + id + "的信息");
    }
}

在另一个方法中调用该对象

package com.spring.controller;
import com.spring.service.MessageService;
public class MessageController {
    private MessageService messageService;
    public void setMessageService(MessageService messageService) {
        this.messageService = messageService;
    }
    public void doGet(Long id) {
        messageService.deleteById(id);
    }
}

在spring-config.xml中这样配置

<?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">
    <!--服务层-->
    <bean id="messageService" class="com.spring.service.MessageService"></bean>
    <!--控制层-->
    <bean id="messageController" class="com.spring.controller.MessageController">
       <!--使用set方式注入-->
        <property name="messageService" ref="messageService"></property>
    </bean>
</beans>

name是类中字段,ref是引入的对象

在测试中这样写

package com.spring.controller;
import com.spring.service.MessageService;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import static org.junit.Assert.*;
public class MessageControllerTest {
    @Test
    public void doGet() {
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring-config.xml");
        MessageController messageController = applicationContext.getBean(MessageController.class);
        messageController.doGet(1L);
    }
}

主要是在xml配置中已经将对象连接起来,之后直接使用就行