从头认识Spring-2.3 注解装配-@autowired（4）-required（2）

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这一章节我们来继续详细讨论一下@autowired里面的参数required，在多构造器注入的情况。

1.domain（重点）

蛋糕类：

package com.raylee.my_new_spring.my_new_spring.ch02.topic_1_10;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_10;import org.springframework.beans.factory.annotation.Autowired;public class Chief {private Cake cake = null;private Oven oven = null;@Autowired(required = false)public Chief(Cake cake) {this.cake = cake;}@Autowired(required = false)public Chief(Cake cake, Oven oven) {this.cake = cake;this.oven = oven;}private String name = "";public String getName() {return name;}public Cake makeOneCake() {if (cake != null) {System.out.println(getName() + " use " + oven.getName() + " and make " + cake.getName());} else {System.out.println("null");}return cake;}public void setName(String name) {this.name = name;}}

厨师类这里需要注意的是，当出现多构造器注入的情况，虽然我们都可以使用@autowired标签，但是需要把required都弄成是false，不然抛异常

还有的是，当出现多构造器注入时，注入成功的是注入对象最多的那个构造器，也就是上面有两个参数的那个

烤炉类：（重新引入）

package com.raylee.my_new_spring.my_new_spring.ch02.topic_1_10;public class Oven {private String name = "";@Overridepublic String toString() {return name;}public String getName() {return name;}public void setName(String name) {this.name = name;}}

2.测试类：（不变）

package com.raylee.my_new_spring.my_new_spring.ch02.topic_1_10;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_10/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.xsd        http://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.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_10.Cake"p:name="blueberryCheeseCake" scope="prototype" /><bean id="bigOven"class="com.raylee.my_new_spring.my_new_spring.ch02.topic_1_10.Oven"p:name="bigOven" /><bean id="jack"class="com.raylee.my_new_spring.my_new_spring.ch02.topic_1_10.Chief"p:name="jack" /></beans>

测试输出：

jack use bigOven and make blueberryCheeseCake

总结：这一章节我们主要讨论了@autowired里面的参数required。

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

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

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