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从头认识Spring-2.3 注解装配-@autowired(5)-限定器@Qualifier(2)

热度:94   发布时间:2023-12-10 03:34:54.0

这一章节我们来继续详细讨论一下配合@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_12;import org.springframework.beans.factory.annotation.Qualifier;@Qualifier("myCake")
public class Cake {private String name = "";public String getName() {return name;}public void setName(String name) {this.name = name;}}

蛋糕类这里需要注意的是:我们在这里加上了@Qualifier标签,大家可以理解成为一种标记,这个类型的标记

厨师类:

package com.raylee.my_new_spring.my_new_spring.ch02.topic_1_12;import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;public class Chief {@Autowired@Qualifier("myCake")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;}}


厨师类这里需要注意的是,在cake上面限定了是myCake这种标记的对象


其实对于上面这种限定方式,大家可以理解成为类似于byType。



2.测试类:(不变)

package com.raylee.my_new_spring.my_new_spring.ch02.topic_1_12;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_12/ApplicationContext-test.xml" })
public class ChiefTest {@Autowiredprivate ApplicationContext applicationContext;@Testpublic 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.xsdhttp://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-2.0.xsdhttp://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsdhttp://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.1.xsdhttp://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.1.xsdhttp://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa-1.0.xsdhttp://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsdhttp://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_12.Cake"p:name="blueberryCheeseCake" scope="prototype" /><bean id="jack"class="com.raylee.my_new_spring.my_new_spring.ch02.topic_1_12.Chief"p:name="jack" />
</beans>

测试输出:

jack make blueberryCheeseCake



4.注意

上面这种方式的注入限定类似于byType,因此他将会出现byType所出现的问题,也就是当有多个bean属于这种标记的时候,spring将无所适从。

下面的地址将给出类似的解决方法:http://blog.csdn.net/raylee2007/article/details/50652283


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


目录:http://blog.csdn.net/raylee2007/article/details/50611627 

 

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


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