从头认识Spring-1.14 SpEl表达式（1）-简介与嵌入值

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这一章节我们来讨论一下SpEl表达式的简介与嵌入值。

1.SpEl表达式简介

Spring Excpression Language (SpEL)语言支持在运行时操作和查询对象

其实就是在运行的过程中操作相应的对象或者值。

2.SpEl嵌入值

（1）domain

蛋糕类：（不变）

package com.raylee.my_new_spring.my_new_spring.ch01.topic_1_14;public class Cake {private int id = 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;}public void setId(int id) {this.id = id;}@Overridepublic String toString() {return "cake id:" + id + " name:" + name + " size:" + size;}}

（2）测试类：（打印蛋糕对象的属性）

package com.raylee.my_new_spring.my_new_spring.ch01.topic_1_14;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_14/ApplicationContext-test.xml" })public class CakeTest {@Autowiredprivate ApplicationContext applicationContext;@Testpublic void testCake() {Cake cake = applicationContext.getBean(Cake.class);System.out.println(cake);}}

（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"xsi:schemaLocation="        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.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="cake"class="com.raylee.my_new_spring.my_new_spring.ch01.topic_1_14.Cake"><property name="id" value="#{1}"/><property name="name" value="#{'blueberry cheese cake'}"/><!-- <property name='name' value='#{"blueberry cheese cake"}'/> --><property name="size" value="#{5.5}"/></bean></beans>

通过#{}把实际的值嵌入到相应的属性里面，当然其实是嵌入值是没什么意思，因为这样已经把程序给写死了。

测试输出：

cake id:1 name:blueberry cheese cake size:5.5

总结：这一章节主要介绍SpEl表达式的简介与嵌入值。

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

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

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