为了解决配置文件中面出现多个同类型的Bean而byType无法匹配的问题。引入了primary和autowire-candidate属性。
1.primary
因为全部bean默认的primary都是true。因此笔者觉得这个属性没有太大的用处
2.autowire-candidate
这个属性的意思是，是否排除自己，假设排除了自己。 那么当使用byType的时候，这个Bean就不列入候选bean里面。看以下的样例：
（1）domain
蛋糕类：（不变）
package com.raylee.my_new_spring.my_new_spring.ch02.topic_1_3;
public class Cake {
private String name = "";
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
厨师类：（不变）
package com.raylee.my_new_spring.my_new_spring.ch02.topic_1_3;
public class Chief {
private Cake cake = null;
private String name = "";
public Cake getCake() {
return cake;
}
public String getName() {
return name;
}
public Cake makeOneCake() {
System.out.println(getName() + " make " + getCake().getName());
return cake;
}
public void setCake(Cake cake) {
this.cake = cake;
}
public void setName(String name) {
this.name = name;
}
}
（2）測试类：（不变）
package com.raylee.my_new_spring.my_new_spring.ch02.topic_1_3; 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_3/ApplicationContext-test.xml" })
public class ChiefTest { @Autowired
private ApplicationContext applicationContext; @Test
public void testChief() {
Chief jack = (Chief) applicationContext.getBean("jack");
jack.makeOneCake();
Chief rose = (Chief) applicationContext.getBean("rose");
rose.makeOneCake();
}
}
（3）配置文件：（重点）
<? 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_3.Cake"
p:name="blueberryCheeseCake" scope="prototype" /> <bean id="cake"
class="com.raylee.my_new_spring.my_new_spring.ch02.topic_1_3.Cake"
p:name="cake" scope="prototype" autowire-candidate="false" /> <bean id="jack"
class="com.raylee.my_new_spring.my_new_spring.ch02.topic_1_3.Chief"
p:name="jack">
<property name="cake" ref="cake" />
</bean> <bean id="rose"
class="com.raylee.my_new_spring.my_new_spring.ch02.topic_1_3.Chief"
autowire="byType" p:name="rose" />
</beans>
上面的配置文件使用autowire-candidate排除了cake这个bean，因此会出现以下的输出。
測试输出：
jack make cake
rose make blueberryCheeseCake
总结：这一章节主要介绍解决配置文件中面出现多个同类型的Bean而byType无法匹配的问题。
文件夹：http://blog.csdn.net/raylee2007/article/details/50611627