这一章节我们来继续具体讨论一下@autowired里面的參数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;

	}

}

厨师类这里须要注意的是，当出现多构造器注入的情况，尽管我们都能够使用@autowired标签。可是须要把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，也就是上面有两个參数的那个

烤炉类：（又一次引入）

package com.raylee.my_new_spring.my_new_spring.ch02.topic_1_10;

public class Oven {

	private String name = "";

	@Override

	public String toString() {

		return name;

	}

	public String getName() {

		return name;

	}

	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_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 {

	@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_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>

測试输出：

jack use bigOven and make blueberryCheeseCake

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

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

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