spring中的idref标签详解

spring中的idref元素

idref元素是一个简单的对容器中存在的另外一个bean的检错途径（通过id）;

<idref bean="someBeanId"/> ，不同于<ref/> someBeanId注入的是一个字符串，相当于：

<property name="targetName" value="someBeanId"/>

如果"someBeanId"不是其中一个bean的ID，将会报BeanDefinitionStoreException

   

详细代码如下：

配置文件：idref_check.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:p="http://www.springframework.org/schema/p"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd">


    <bean id="shihaofengqiu"
          class="beans.Song"
          p:title="十号风球"/>

    <bean id="xiaoming"
          class="beans.Singer">
        <property name="name" value="xiaoming"/>
        <!--<property name="song" value="mrfanl"/>-->
        <property name="song">
            <!--<idref bean="mrfanl"/>--><!--报错-->
            <idref bean="shihaofengqiu"/><!--通过-->
        </property>
    </bean>
</beans>

 

performer.java

package beans;

public interface Performer {
    public void play();
}

Singer.java

package beans;

public class Singer implements Performer {

    private String name;
    private String song;

    public Singer() {

    }

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

    public void setSong(String song) {
        this.song = song;
    }

    @Override
    public void play() {
        System.out.println("my name is:"+this.name);
        System.out.println("my song is:"+this.song);

    }
}

Song.java

package beans;

public class Song {
    private String title;

    public Song(){}

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }
}

test.java

package main;

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

public class test {
    public static void main(String[] args){
        ApplicationContext ctx = new ClassPathXmlApplicationContext("idref_check.xml");
        Performer xiaoming = (Performer) ctx.getBean("xiaoming");
        xiaoming.play();
    }
}

结果：