从头认识Spring-1.15 对SpEl的值的操作（1）-数值运算

这一章节我们来讨论一下对SpEl的值的运算。

1.domain

烤炉类：（不变）

package com.raylee.my_new_spring.my_new_spring.ch01.topic_1_17;

public class Oven {
	private String name = "";

	private double size = 0;

	public double getSize() {
		return size;
	}

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

	@Override
	public String toString() {
		return name + " size:" + size;
	}

	public String getName() {
		return name;
	}

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

}

厨师类：（为了方便，降低了friend的属性）

package com.raylee.my_new_spring.my_new_spring.ch01.topic_1_17;

public class Chief {

	private String name = "";

	private Oven oven;

	public String getName() {
		return name;
	}

	public Oven getOven() {
		return oven;
	}

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

	public void setOven(Oven oven) {
		this.oven = oven;
	}

	public void userOven() {
		System.out.println(name + " use " + oven);
	}

}

2.測试类：（不变）

package com.raylee.my_new_spring.my_new_spring.ch01.topic_1_17;

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_17/ApplicationContext-test.xml" })
public class ChiefTest {

	@Autowired
	private ApplicationContext applicationContext;

	@Test
	public void testChief() {
		Chief jack = (Chief) applicationContext.getBean("jack");
		jack.userOven();
		Chief mike = (Chief) applicationContext.getBean("mike");
		mike.userOven();
		Chief rose = (Chief) applicationContext.getBean("rose");
		rose.userOven();
	}
}

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"
	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="smallOven"
		class="com.raylee.my_new_spring.my_new_spring.ch01.topic_1_17.Oven"
		p:name="smallOven" p:size="#{2*3}" />

	<bean id="midOven"
		class="com.raylee.my_new_spring.my_new_spring.ch01.topic_1_17.Oven"
		p:name="smallOven" p:size="#{T(java.lang.Math).PI*4}" />

	<bean id="bigOven"
		class="com.raylee.my_new_spring.my_new_spring.ch01.topic_1_17.Oven"
		p:name="smallOven" p:size="#{smallOven.getSize()*4}" />

	<bean id="mike"
		class="com.raylee.my_new_spring.my_new_spring.ch01.topic_1_17.Chief"
		p:name="mike">
		<property name="oven" ref="smallOven" />
	</bean>

	<bean id="jack"
		class="com.raylee.my_new_spring.my_new_spring.ch01.topic_1_17.Chief"
		p:name="jack">
		<property name="oven" ref="midOven" />
	</bean>

	<bean id="rose"
		class="com.raylee.my_new_spring.my_new_spring.ch01.topic_1_17.Chief"
		p:name="rose">
		<property name="oven" ref="bigOven" />
	</bean>
</beans>

配置文件的重点就是看Oven里面的size属性。在这里我们能够通过执行符来计算我们须要的值，直接对SpEl的值进行操作。

測试输出：

jack use smallOven size:12.566370614359172
mike use smallOven size:6.0
rose use smallOven size:24.0

我们上面仅仅是演示了乘法，它有：+ 加 - 减 * 乘 / 除 % 模 ^平方 这几种运算方式，大家后面能够逐一尝试。

总结：这一章节我们讨论了对SpEl的值的运算。

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

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