从头认识Spring-1.7 怎样通过属性注入Bean？（2）-怎样通过属性向对象注入另一个对象的引用？

这一章节我们继续上面的话题。

2.怎样通过属性向对象注入另一个对象的引用？

（1）domain

我们除了蛋糕类，还需要引用前面的厨师类

package com.raylee.my_new_spring.my_new_spring.ch01.topic_1_7;

public class Cake {

	private final int id = index++;

	private static int index = 0;

	private String name = "";

	private double size = 0;

	public String getName() {
		return name;
	}

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

	public double getSize() {
		return size;
	}

	public void setSize(double size) {
		this.size = size;
	}

	public int getId() {
		return id;
	}

	@Override
	public String toString() {
		return "create the cake,its id:" + id + ", size:" + size + " inch ,name:" + name;
	}
}

蛋糕类不变

package com.raylee.my_new_spring.my_new_spring.ch01.topic_1_7;

public class Chief {

	private Cake cake = null;

	public Cake getCake() {
		return cake;
	}

	private String name = "";

	public Chief(String name) {
		this.name = name;
	}

	public String getName() {
		return name;
	}

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

	public void setCake(Cake cake) {
		this.cake = cake;
	}

	private final int id = index++;

	public int getId() {
		return id;
	}

	private static int index = 0;

	public Cake makeOneCake() {
		return cake;
	}

}

我们在厨师类上面加上蛋糕这一个属性，同时也为这个厨师加上名称属性

（2）测试类

package com.raylee.my_new_spring.my_new_spring.ch01.topic_1_7;

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/ch01/topic_1_7/ApplicationContext-test.xml" })
public class ChiefTest {

	@Autowired
	private ApplicationContext applicationContext;

	@Test
	public void testChief() {
		Chief chief = applicationContext.getBean(Chief.class);
		System.out.println("chief name:" + chief.getName());
		System.out.println(chief.getName() + " make a cake ,cake‘s name :" + chief.makeOneCake().getName());
	}
}

主要负责get那个Bean，然后打印厨师的名称和所做的蛋糕

（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:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:tx="http://www.springframework.org/schema/tx"
	xmlns:aop="http://www.springframework.org/schema/aop"
	xsi:schemaLocation="
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.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="cake"
		class="com.raylee.my_new_spring.my_new_spring.ch01.topic_1_7.Cake">
		<property name="name" value="Blueberry Cheesecake" />
		<property name="size" value="7" />
	</bean>
	<bean id="chief"
		class="com.raylee.my_new_spring.my_new_spring.ch01.topic_1_7.Chief">
		<constructor-arg value="jack" />
		<property name="cake" ref="cake" />
	</bean>

</beans>

配置文件里面

A.cake不变

B.在chief的Bean里面引用上面已经生产的cake的Bean，同时也在构造器里面赋予名称

但是这里需要注意一点的是：ref里面的值，必须是你配置文件里面拥有的Bean的id，这里严格大小写，也就是说

<bean id="chief"
		class="com.raylee.my_new_spring.my_new_spring.ch01.topic_1_7.Chief">
		<constructor-arg value="jack" />
		<property name="cake" ref="Cake" />
	</bean>

和

<bean id="chief"
		class="com.raylee.my_new_spring.my_new_spring.ch01.topic_1_7.Chief">
		<constructor-arg value="jack" />
		<property name="cake" ref="cake" />
	</bean>

两者完全是不一样的

测试输出：

chief name:jack
jack make a cake ,cake‘s name :Blueberry Cheesecake

总结：这一章节主要介绍了怎样通过属性向对象注入另一个对象的引用，还有里面需要注意的地方。

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

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