spring注解方式注入bean

用注解的方式注入bean，spring的配置文件也要增加一些约束和导入注解所在的包

applicationContext.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.xsd">

     <context:component-scan base-package="com.xiaostudy.service"></context:component-scan>
     <context:component-scan base-package="com.xiaostudy.dao"></context:component-scan>
 </beans>

用注解注入的bean类PersonImple.java

 package com.xiaostudy.service;

 import javax.annotation.PostConstruct;
 import javax.annotation.PreDestroy;
 import javax.annotation.Resource;

 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.context.annotation.Scope;
 import org.springframework.stereotype.Component;
 /*
  * bean注入
  * 1、@Component("id")
  * 2、WEB:
  *             @Controller("id")    web
  *             @Service("id")        service
  *            @Repository("id")    dao
  */
 @Component("person")
 /*
  * bean作用域
  * @Scope("singleton")        单例（也是默认）
  * @Scope("prototype")        每new一次都是新的对象
  */
 @Scope("prototype")
 public class PersonImple implements Person {
     /*
      * bean参数注入
      * 1、普通参数（也就是说那些基本数据类型）
      *         在参数上面或者在相应的set方法    @Value("值")
      * 2、引用参数
      *         2.1按照类型注入：@Autowired
      *         2.2按照名称注入：@Autowired    @Qualifier("id")
      *         2.3按照名称注入：@Resource
      *
      */
     //@Resource
     private Dao_demoImple dao_demo;
     @Value("xiaostudy")
     private String name;

     public String getName() {
         return name;
     }

     public void setName(String name) {
         this.name = name;
     }

     public Dao_demoImple getDao_demo() {
         return dao_demo;
     }

     @Resource
     public void setDao_demo(Dao_demoImple dao_demo) {
         this.dao_demo = dao_demo;
     }
     /*
      * bean初始化方法注解
      *         @PostConstruct
      */
     @PostConstruct
     public void init() {
         System.out.println("init()>>>>>>");
     }

     /*
      * bean销毁注解
      *         @PreDestroy
      */
     @PreDestroy
     public void destroy() {
         System.out.println("destroy()>>>>>");
     }

 }

Person接口

 package com.xiaostudy.service;

 public interface Person {

 }

Dao_demo接口

 package com.xiaostudy.dao;

 public interface Dao_demo {

 }

Dao_demoImple.java

 package com.xiaostudy.service;

 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.stereotype.Component;

 import com.xiaostudy.dao.Dao_demo;
 @Component("dao_demo")
 public class Dao_demoImple implements Dao_demo {

     private String name;

     public String getName() {
         return name;
     }

     @Value("demo")
     public void setName(String name) {
         this.name = name;
     }

     public void add() {
         System.out.println("add>>>>>>");
     }

 }

测试类Test.java

 package com.xiaostudy.service;

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

 import com.xiaostudy.dao.Dao_demo;
 import com.xiaostudy.service.Person;

 public class Test {

     public static void main(String[] args) {
         ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");
         Person person = ac.getBean("person", Person.class);
         System.out.println(person);
         PersonImple pi = (PersonImple)person;
         System.out.println(pi.getName());
         Dao_demoImple dao_demo = pi.getDao_demo();
         System.out.println(dao_demo);
         dao_demo.add();
         System.out.println(dao_demo.getName());
         /*Person person1 = ac.getBean("person", Person.class);
         Person person2 = ac.getBean("person", Person.class);
         System.out.println(person1);
         System.out.println(person2);
         ((AbstractApplicationContext) ac).close();*/
     }

 }

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