Spring学习笔记（八）模拟实际开发过程的调用过程注解版-传统方式

传统的@Component和@Resource(等价于XML版setter注入)使用说明

@Component是个泛化概念，可以用在任何层次

源码获取github

1.项目结构(jar同上)

2.核心配置文件beans.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:context="http://www.springframework.org/schema/context" xmlns:p="http://www.springframework.org/schema/p" xmlns:util="http://www.springframework.org/schema/util" xmlns:aop="http://www.springframework.org/schema/aop" xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.3.xsd http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.3.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.3.xsd http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-4.3.xsd">
   <!--1.启动Spring注解-->
   <context:annotation-config></context:annotation-config>
   <!--2.扫描-->
   <context:component-scan base-package="com.hs"/>

</beans>

3.dao层

userDao.java

package com.hs.dao;

public interface UserDao {
   void add();
}

UserDaoImpl.java

package com.hs.dao.impl;

import com.hs.dao.UserDao;
import org.springframework.stereotype.Component;

@Component//(value = "userDao") //相当于<bean id="userDaoImpl" class="com.hs.dao.impl.UserDaoImpl"/>
public class UserDaoImpl implements UserDao {

   @Override
   public void add() {
      System.out.println("UserDao层的实现类--->ADD");
   }
}

4.Service层

UserService.java

package com.hs.service;

public interface UserService {


   void add();
}

UserServiceImpl.java

package com.hs.service.impl;

import com.hs.dao.UserDao;
import com.hs.service.UserService;
import org.springframework.stereotype.Component;

import javax.annotation.Resource;

@Component  //相当于<bean id="userServiceImpl" class="com.hs.service.impl.UserServiceImpl">
public class UserServiceImpl implements UserService {

   private UserDao userDao;

   public UserDao getUserDao() {
      return userDao;
   }

   /*相当于<property name="userDao"> <ref bean="userDaoImpl"/> </property>*/
   @Resource(name = "userDaoImpl")
   //下面的查找顺序 先按照名字进行搜索(没有写名字默认就是set后面那个名字) 再按照类型进行搜索(UserDao的实现类)
   //@Resource
   public void setUserDao(UserDao userDao) {
      this.userDao = userDao;
   }

   @Override
   public void add() {
      System.out.println("UserService层的实现类--->ADD");
      this.userDao.add();
   }
}

知识点：@Resource注解

• 先按名称搜索，再按照类型搜索

• 是javax下的，不是Spring自带的

• 后面会有Spring自带的注解@Autowired推荐

5.Controller层

UserController.java

package com.hs.web;

import com.hs.service.UserService;
import org.springframework.stereotype.Component;

import javax.annotation.Resource;

@Component  //相当于<bean id="userController" class="com.hs.web.UserController"/>
public class UserController {
   //简写方式，写个就不用写set方法了
   //如果你所在的公司用了测试框架(不是我现在用的单元测试框架)，那么不建议使用简写方式，对测试有影响
   //@Resource(name = "userServiceImpl")
   private UserService userService;

   public UserService getUserService() {
      return userService;
   }

   @Resource(name = "userServiceImpl") //相当于p:userService-ref="userServiceImpl"
   public void setUserService(UserService userService) {
      this.userService = userService;
   }
   public void add() {
      System.out.println("UserController层--->ADD");
      this.userService.add();
   }

}

6.测试

package com.hs.test;

import com.hs.web.UserController;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class MethodTest {
   @Test
   public void test01() {
      ApplicationContext applicationContext = new ClassPathXmlApplicationContext("beans.xml");
      UserController controller = applicationContext.getBean("userController", UserController.class);
      controller.add();
   }
}