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();*/
    }

}

---