Spring初学之annotation自动装配

Posted 2020-09-10

直接看代码：

UserController.java

package spring.beans.annotation.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;

import spring.beans.annotation.service.UserService;

@Controller
public class UserController {
    
    @Autowired
    private UserService userService;
    public  void add() {

        System.out.println("UserController add...");
        userService.add();
    }
}

UserService.java

package spring.beans.annotation.service;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Service;

import spring.beans.annotation.repository.UserRepository;
import spring.beans.annotation.repository.UserRepositoryImpl;

@Service
public class UserService {
    
    @Autowired
    @Qualifier("userRepositoryImpl")
    private UserRepository userRepository;
    public void add(){
        System.out.println("UserService add...");
        userRepository.add();
    }
}

UserRepository.java

package spring.beans.annotation.repository;

public interface UserRepository {
    public void add();
}

UserRepositoryImpl.java

package spring.beans.annotation.repository;

import org.springframework.stereotype.Repository;



@Repository//("userRepository")
//这里设置的value="userRepository",也可以用@Qualifier("userRepositoryImpl")写在装配它的地方
public class UserRepositoryImpl implements UserRepository {

    @Override
    public void add() {
        System.out.println("UserRepositoryImpl add...");
    }

}

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: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-4.3.xsd">

    <!-- 扫描指定spring IOC容器的类 -->
    <!--使用resource-pattern扫描特定的类 -->
    <!-- 
    <context:component-scan base-package="spring.beans.annotation"
        resource-pattern="repository/*.class">
    </context:component-scan>
     -->
     
     <!-- 筛选扫描 --> 
    <context:component-scan base-package="spring.beans.annotation"
    >
        <!-- 扫描不包含指定类型（表达式）的类 -->
        <!-- 
        <context:exclude-filter type="annotation" 
        expression="org.springframework.stereotype.Repository"/>
         -->
         <!-- 扫描包含指定类型（表达式）的类(context下设置use-default-filters="false")配合使用 -->
         <!-- <context:include-filter type="annotation" 
         expression="org.springframework.stereotype.Repository"/>
          -->
          <!-- 扫描除了该接口 或该接口实现类的类 -->
          <!-- <context:exclude-filter type="assignable" 
          expression="spring.beans.annotation.repository.UserRepository"/>
           -->
          <!-- 只扫描包含该接口 或该接口实现类的类 (context下设置use-default-filters="false")配合使用-->
          <!-- <context:include-filter type="assignable" 
          expression="spring.beans.annotation.repository.UserRepository"/>
             -->
    </context:component-scan>
    
</beans>