从头认识Spring-1.14 SpEl表达式（1）-简单介绍与嵌入值

这一章节我们来讨论一下SpEl表达式的简单介绍与嵌入值。

1.SpEl表达式简单介绍

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

事实上就是在执行的过程中操作对应的对象或者值。

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;
}

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

}

（2）測试类：（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 {

@Autowired
private ApplicationContext applicationContext;

@Test
public 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.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_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#{}把实际的值嵌入到对应的属性里面。当然事实上是嵌入值是没什么意思，由于这样已经把程序给写死了。

測试输出：

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

总结：这一章节主要介绍SpEl表达式的简单介绍与嵌入值。

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

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