Spring HTTP invoker 入门

一、简介

Spring开发团队意识到RMI服务和基于HTTP的服务（如，Hessian）之间的空白。一方面，RMI使用JAVA标准的对象序列化机制，很难穿透防火墙。另一方面，Hessian/Burlap能很好的穿透防火墙，但是使用私有的对象序列化机制。
    由此，Spring的HTTP invoker应运而生。HTTP invoker是一个新的远程调用模型，作为Spring框架的一部分，来执行基于HTTP的远程调用（穿透防火墙），并使用Java的序列化机制。

二、发布HTTP服务

1、编写接口

 package com.cnblogs.javalouvre.service;

 public interface GreetService {

     String sayHello(String name);

 }

2、编写实现类

 package com.cnblogs.javalouvre.service;

 public class GreetServiceImpl implements GreetService {

     @Override
     public String sayHello(String name) {
         return "Hello " + name;
     }

 }

3、配置Spring文件(remoting-servlet.xml)

 <?xml version="1.0" encoding="UTF-8"?>
 <beans xmlns="http://www.springframework.org/schema/beans"
        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-4.0.xsd">

   <bean id="greetService" class="com.cnblogs.javalouvre.service.GreetServiceImpl" />

   <bean name="/GreetService" class="org.springframework.remoting.httpinvoker.HttpInvokerServiceExporter">
     <property name="service" ref="greetService" />
     <property name="serviceInterface" value="com.cnblogs.javalouvre.service.GreetService" />
   </bean>

 </beans>

4、配置WEB文件(web.xml)

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
    version="2.5">

    <servlet>
        <servlet-name>remoting</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>remoting</servlet-name>
        <url-pattern>/remoting/*</url-pattern>
    </servlet-mapping>

    <welcome-file-list>
        <welcome-file>index.html</welcome-file>
        <welcome-file>index.htm</welcome-file>
        <welcome-file>index.jsp</welcome-file>
    </welcome-file-list>

</web-app>

三、客户端调用

1、配置Spring文件

 <?xml version="1.0" encoding="UTF-8"?>
 <beans xmlns="http://www.springframework.org/schema/beans"
        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-4.0.xsd">

   <bean id="greetService" class="org.springframework.remoting.httpinvoker.HttpInvokerProxyFactoryBean">
     <property name="serviceUrl" value="http://10.108.1.138:8080/remoting/GreetService"/>
     <property name="serviceInterface" value="com.cnblogs.javalouvre.service.GreetService"/>
   </bean>

 </beans>

2、编写客户端测试

 package com.cnblogs.javalouvre.client;

 import org.springframework.context.ApplicationContext;
 import org.springframework.context.support.ClassPathXmlApplicationContext;

 import com.cnblogs.javalouvre.service.GreetService;

 public class Client {

     public static void main(String[] args) {
         ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
         GreetService service = context.getBean("greetService", GreetService.class);
         System.out.println(service.sayHello("Jobs"));
     }

 }