大前提：

 添加了相关的约束文件以及注解支持

<?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/beanshttp://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/contexthttp://www.springframework.org/schema/context/spring-context.xsd"><context:annotation-config/></beans>

package org.example.eneity;import org.springframework.stereotype.Component;@Component
public class User {public String name="张三";}

public String name=" 张三 ”可以如下这么写

package org.example.entity;import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;@Component
public class User {@Value("张三")public String name;}

 

@Componen注解的作用相当于创建了一个bean

@Component = <bean id =" user " class=" org.example.eneity.User " /> 

 beans.xml

<context:component-scan base-package="org.example.entity"/>

它的作用是：指定扫描这个包，在这个包下的注解会生效 

 

测试

public class Test10 {public static void main(String[] args) {ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");User user=(User) context.getBean("user");System.out.println(user.name);}
}