从头认识Spring-2.3 注解装配-@autowired-限定器@Qualifier

Posted 2020-09-29 llguanli

这一章节我们来具体讨论一下配合@autowired一起使用的限定器@Qualifier。

1.domain（重点）

蛋糕类：

package com.raylee.my_new_spring.my_new_spring.ch02.topic_1_11;

public class Cake {

	private String name = "";

	public String getName() {
		return name;
	}

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

}

厨师类：

package com.raylee.my_new_spring.my_new_spring.ch02.topic_1_11;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;

public class Chief {
	@Autowired
	@Qualifier("cake")
	private Cake cake = null;

	private String name = "";

	public String getName() {
		return name;
	}

	public Cake makeOneCake() {
		if (cake != null) {
			System.out.println(getName() + " make " + cake.getName());
		} else {
			System.out.println(cake);
		}
		return cake;
	}

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

}

厨师类这里须要注意的是，因为配置文件可能出现多个满足cake的bean。因此我们在chief里面使用限定器@Qualifier，限定了cake属性的注入对象仅仅可以是beanid是cake的bean。

2.測试类：（不变）

package com.raylee.my_new_spring.my_new_spring.ch02.topic_1_11;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = {
		"/com/raylee/my_new_spring/my_new_spring/ch02/topic_1_11/ApplicationContext-test.xml" })
public class ChiefTest {

	@Autowired
	private ApplicationContext applicationContext;

	@Test
	public void testChief() {
		Chief jack = applicationContext.getBean(Chief.class);
		jack.makeOneCake();
	}
}

3.配置文件

<?
xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:context="http://www.springframework.org/schema/context" xmlns:p="http://www.springframework.org/schema/p"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:tx="http://www.springframework.org/schema/tx"
	xmlns:aop="http://www.springframework.org/schema/aop" xmlns:util="http://www.springframework.org/schema/util"
	xsi:schemaLocation="
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
        http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-2.0.xsd
		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd
		http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.1.xsd
		http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.1.xsd
		http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa-1.0.xsd
		http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd">
	<bean id="blueberryCheeseCake"
		class="com.raylee.my_new_spring.my_new_spring.ch02.topic_1_11.Cake"
		p:name="blueberryCheeseCake" scope="prototype" />
	<bean id="cake"
		class="com.raylee.my_new_spring.my_new_spring.ch02.topic_1_11.Cake"
		p:name="cake" scope="prototype" />
	<bean id="jack"
		class="com.raylee.my_new_spring.my_new_spring.ch02.topic_1_11.Chief"
		p:name="jack" />
</beans>

配置文件须要注意的地方是：我们为了測试上面的样例。有益定义了两个Cake类型的bean

測试输出：

jack make cake

总结：这一章节我们主要讨论了@autowired里面的限定器@Qualifier。

文件夹：http://blog.csdn.net/raylee2007/article/details/50611627 

 

我的github：https://github.com/raylee2015/my_new_spring