2021-05-03 09:46  阅读(184)
文章分类:Spring 入门教程 文章标签:SpringSpring 教程
©  原文作者:一点教程 原文地址:http://www.yiidian.com/spring/

在Spring3中就已经支持EL表达式了, Spring Expression Language(SpEL)是类似于OGNLJSF EL的表达式语言, 能够在运行时构建复杂表达式, 存取对象属性、调用对象方法等, 而且所有的SpEL都支持XML和Annotation两种方式, 使用的格式均为:#{SpEL expression}。

下面的例子,这个例子将展示如何利用SpEL注入String、Bean到属性中。

一、编写Bean类

Customer.java

    
    package com.yiidian.domain;
    
    import java.io.Serializable;
    /**
     * 
     * @author http://www.yiidian.com
     *
     */
    public class Customer implements Serializable{
    	private String name;
    	private String telephone;
    	public String getName() {
    		return name;
    	}
    	public void setName(String name) {
    		this.name = name;
    	}
    	public String getTelephone() {
    		return telephone;
    	}
    	public void setTelephone(String telephone) {
    		this.telephone = telephone;
    	}
    }

CustomerDao接口:

    
    
    
    /**
     * 
     * @author http://www.yiidian.com
     *
     */
    public interface CustomerDao {
    }

CustomerDaoImpl类:

注意:在这个类中注入Customer对象和custName的字符串。

    
    package com.yiidian.dao.impl;
    
    import com.yiidian.dao.CustomerDao;
    import com.yiidian.domain.Customer;
    /**
     * @author http://www.yiidian.com
     *
     */
    public class CustomerDaoImpl implements CustomerDao {
    	
    	private Customer customer;
    	private String custName;
    	public void setCustomer(Customer customer) {
    		this.customer = customer;
    	}
    	public void setCustName(String custName) {
    		this.custName = custName;
    	}
    
    	@Override
    	public String toString() {
    		return "CustomerDaoImpl [customer=" + customer + ", custName=" + custName + "]";
    	}
    	
    }

二、编写applicationContext.xml

    
    <?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans"
    	xmlns:p="http://www.springframework.org/schema/p"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="
            http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
    
    	<bean id="customer" class="com.yiidian.domain.Customer">
    		<property name="name" value="张三"/>
    		<property name="telephone" value="13666666666"/>
    	</bean>
    
    	 <bean id="customerDao" class="com.yiidian.dao.impl.CustomerDaoImpl">
    	 	<!--
    	 		 #{customer}:注入Customer对象
    	 		 #{customer.name}: 注入Cutomer的name属性值
    	 	 -->
    	 	 <property name="customer" value="#{customer}"></property>
    	 	 <property name="custName" value="#{customer.name}"></property>
    	 </bean>
        
    </beans>

三、编写测试

    
    package com.yiidian.test;
    
    import org.junit.Test;
    import org.springframework.context.ApplicationContext;
    import org.springframework.context.support.ClassPathXmlApplicationContext;
    
    import com.yiidian.dao.CustomerDao;
    
    /**
     * @author http://www.yiidian.com
     * 
     */
    public class Demo1 {
    
    	@Test
    	public void test1() {
    		ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
    		CustomerDao customerDao = (CustomerDao)context.getBean("customerDao");
    		System.out.println(customerDao);
    	}
    
    }
    

四、运行结果

202105030946024010_1.png

源码下载:http://pan.baidu.com/s/1i4HlQzb

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