Spring 在 xml配置文件或annotation注解中运用Spring EL

Spring  EL
一：在Spring xml 配置文件中运用   Spring EL
Spring EL 采用 #{Sp Expression  Language} 即 #{spring表达式}
1：运用EL表达式的配置文件如下：

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"xsi:schemaLocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans-3.0.xsdhttp://www.springframework.org/schema/contexthttp://www.springframework.org/schema/context/spring-context-3.0.xsd">  <!-- more bean definitions for data access objects go here -->    <bean id="book" class="com.myapp.core.spel.xml.Book">   <property name="name" value="Effective Java" />   <property name="pages" value="300"/>  </bean>      <bean id="person" class="com.myapp.core.spel.xml.Person">    <property name="book" value="#{book}" />    <property name="bookName" value="#{book.name}"/>   </bean></beans>

在person  bean 的配置中， 属性 book 引用了  book bean 通过EL表达式 形式是：<property name="book" value="#{book}" /> 相当于 在person bean中注入 book
person属性中的bookName属性注入了 book bean中的 name的值  
2：测试以上配置：
Book类：

package com.myapp.core.spel.xml;public class Book {private  String  name ;private  int   pages;  public String getName() {return name;}public void setName(String name) {this.name = name;}public int getPages() {return pages;}public void setPages(int pages) {this.pages = pages;}  }

Person类：

package com.myapp.core.spel.xml;public class Person {   private  Book  book;      private  String  bookName;public void setBook(Book book) {this.book = book;}public Book getBook(){ return  this.book;}public  String   getBookName(){return  this.bookName;}public void setBookName(String bookName) {this.bookName = bookName;}}

测试类：

package com.myapp.core.spel.xml;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;public class MainTest { public static void main(String[] args) {ApplicationContext  context  = new  ClassPathXmlApplicationContext("resource/spel.xml");Person  person =  (Person)context.getBean("person");System.out.println(person.getBookName());System.out.println(person.getBook().getPages());}}

输出结果：

三月 18, 2013 5:17:18 下午 org.springframework.context.support.AbstractApplicationContext prepareRefreshINFO: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@11e831: startup date [Mon Mar 18 17:17:18 CST 2013]; root of context hierarchy三月 18, 2013 5:17:18 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitionsINFO: Loading XML bean definitions from class path resource [resource/spel.xml]三月 18, 2013 5:17:18 下午 org.springframework.beans.factory.support.DefaultListableBeanFactory preInstantiateSingletonsINFO: Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@498b39: defining beans [book,person]; root of factory hierarchyEffective Java300

二：注解中使用 EL
1：xml中配置，扫描含有注解的包；

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"xsi:schemaLocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans-3.0.xsdhttp://www.springframework.org/schema/contexthttp://www.springframework.org/schema/context/spring-context-3.0.xsd">  <!-- more bean definitions for data access objects go here -->  <context:component-scan base-package="com.myapp.core.spel.annotation" />      </beans>

2：相应的类：

Book类：

package com.myapp.core.spel.annotation;import org.springframework.beans.factory.annotation.Value;import org.springframework.stereotype.Component;@Component("book")public class Book {@Value("Effective Java")private  String  name ;@Value("300")private  int   pages;  public String getName() {return name;}public void setName(String name) {this.name = name;}public int getPages() {return pages;}public void setPages(int pages) {this.pages = pages;}}

在book的属性中 注入了值。

Person类：

package com.myapp.core.spel.annotation;import org.springframework.beans.factory.annotation.Value;import org.springframework.stereotype.Component;@Component("person")public class Person {     @Value("#{book}")   private  Book  book;     @Value("#{book.name}")   private  String  bookName;public void setBook(Book book) {this.book = book;}public Book getBook(){ return  this.book;}public  String   getBookName(){return  this.bookName;}public void setBookName(String bookName) {this.bookName = bookName;}}

测试类：

package com.myapp.core.spel.annotation;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;public class MainTest { public static void main(String[] args) {ApplicationContext  context  = new  ClassPathXmlApplicationContext("resource/spel.xml");Person  person =  (Person)context.getBean("person");System.out.println(person.getBookName());System.out.println(person.getBook().getPages());}}

测试结果：

三月 18, 2013 5:25:23 下午 org.springframework.context.support.AbstractApplicationContext prepareRefreshINFO: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@11e831: startup date [Mon Mar 18 17:25:23 CST 2013]; root of context hierarchy三月 18, 2013 5:25:23 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitionsINFO: Loading XML bean definitions from class path resource [resource/spel.xml]三月 18, 2013 5:25:24 下午 org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider registerDefaultFiltersINFO: JSR-330 'javax.inject.Named' annotation found and supported for component scanning三月 18, 2013 5:25:24 下午 org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor <init>INFO: JSR-330 'javax.inject.Inject' annotation found and supported for autowiring三月 18, 2013 5:25:24 下午 org.springframework.beans.factory.support.DefaultListableBeanFactory preInstantiateSingletonsINFO: Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@543360: defining beans [book,person,org.springframework.context.annotation.internalConfigurationAnnotationProcessor,org.springframework.context.annotation.internalAutowiredAnnotationProcessor,org.springframework.context.annotation.internalRequiredAnnotationProcessor,org.springframework.context.annotation.internalCommonAnnotationProcessor]; root of factory hierarchyEffective Java300