spring-06-anno_anno spring-优快云博客

本文链接：https://blog.youkuaiyun.com/qq_53327720/article/details/120379140

本文通过一个简单的例子展示了如何使用Spring框架进行组件扫描和依赖注入。具体包括定义了Controller、Service、DAO层及POJO类，并通过XML配置文件启用注解支持和指定扫描包，最终通过测试类获取Bean并输出结果。

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package com.xu.controller;

import org.springframework.stereotype.Controller;
@Controller
public class UserController {
}

package com.xu.dao;

import org.springframework.stereotype.Repository;
@Repository
public class UserDao {
}

package com.xu.pojo;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
//等价于bean配置
@Component
public class User {
    @Value("nihaoya")
    public String name="你好呀";
}

package com.xu.service;

import org.springframework.stereotype.Service;
@Service
public class UserService {
}

<?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.xsd">
    <!--    开启注解的支持-->
<!--    指定要扫描的包，这个包下的注解就会生效-->
    <context:component-scan base-package="com.xu.pojo"/>
    <context:annotation-config/>
</beans>

import com.xu.pojo.User;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class MyTest {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        User user = (User) context.getBean("user");
        System.out.println(user.name);
    }
}