1.在classpath当中扫组件

Spring能够从classpath下自动扫描,侦测和实例化具有特定注解的组件
特定组件包括：
@Component:基本组件
@Respository:标识持久层组件
@Service:标识服务层组件
@Controller:标识表现层组件
开启注解：<context:component-scan/>
<context:component-scan/>该元素还会自动注册AutowireAnnotationBeanPostProcessor实例，该实例可以自动装配具有@Autowire,@Resource,@Inject注解的属性。

<?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">
    
    <!-- 
        指定Spring IOC容器要扫描的包 
        可以通过resourc指定扫描的资源(此处是扫描repository下的所有类)，注意是指定包，不会扫描其子包
        resource-pattern="repository/*.class"
        
        context:exclude-filter指定排除那些表达式组件
        <context:exclude-filter type="annotation" expression="org.springframework.stereotype.Repository"/>
        
    -->
    
    <context:component-scan base-package="com.sprign.annotiction" use-default-filters="false">
        <!-- <context:exclude-filter type="annotation" expression="org.springframework.stereotype.Repository"/> -->
        <!-- 指定包含哪些组件的时候，一定要设置use-default-filters="false"，否则全包括 -->
        <context:include-filter type="annotation" expression="org.springframework.stereotype.Repository"/>
    </context:component-scan>

</beans>
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package com.sprign.annotiction;

import org.springframework.stereotype.Component;

@Component
public class TestObject {

}
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package com.sprign.annotiction.repository;

public interface UserRepository {

    public void save();
}

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package com.sprign.annotiction.repository.impl;

import org.springframework.stereotype.Repository;

import com.sprign.annotiction.repository.UserRepository;

@Repository
public class UserRepositoryImpl implements UserRepository {

    @Override
    public void save() {
        
        System.out.println("UserRepository Save...");
    }
}
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package com.sprign.annotiction.service;

import org.springframework.stereotype.Service;

@Service
public class UserService {

    public void add() {
        System.out.println("UserServiece add...");
    }
}
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package com.sprign.annotiction.controller;

import org.springframework.stereotype.Controller;

@Controller
public class UserCotroller {

    public void execute() {
        System.out.println("UserController execute...");
    }
}

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package com.sprign.annotiction;

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

import com.sprign.annotiction.controller.UserCotroller;
import com.sprign.annotiction.repository.UserRepository;
import com.sprign.annotiction.service.UserService;

public class Main {

    public static void main(String[] args) {
        
        ApplicationContext ctx=new ClassPathXmlApplicationContext("beans-annotation.xml");
        TestObject to=(TestObject) ctx.getBean("testObject");
        UserCotroller uc=(UserCotroller) ctx.getBean("userCotroller");
        UserService us=(UserService) ctx.getBean("userService");
//      UserRepository ur=(UserRepository) ctx.getBean("userRepositoryImpl");
        System.out.println(to);
        System.out.println(uc);
        System.out.println(us);
//      System.out.println(ur);
        
    }
}