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  • 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



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  • 原文地址:https://www.cnblogs.com/brucemengbm/p/7395996.html
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