Hessian和Burlap入门教程

一、简介

Hessian和Burlap是由Caucho Technology提供的基于HTTP协议的轻量级远程服务解决方案。他们都致力于借助尽可能简单那的API和通信协议来简化Web服务。
    Hession和Burlap就如同一个事物的两面，但是每一个解决方案都服务于略微不同的目的。Hession就像RMI一样，使用二进制尽心客户端和服务端的交互。但与其他二进制远程调用技术（如，RMI）不同的是，它的二进制消息可以移植到其他开发语言中（如，PHP、Python、C++、C#）。Burlap是一种基于XML的远程调用技术，这使得它可以自然而然的移植到任何能够解析XML的语言上。正因为如此，Burlap比起Hessian的二进制格式而言有更强的可读性。但，与其他基于XML的远程技术（如，SOAP、XML-RPC）不同，Burlap的消息结构尽可能的简单，不需要额外的外部定义语言（如，WSDL、IDL）。
    你可能想知道如何在Hession和Burlap之间抉择，很大程度，他们是一样的。唯一的区别在于Hession的消息似乎二进制的，在带宽上更有优势，而Burlap的消息是XML的，有更好的可读性。
    由于Hessian和Burlap都是基于HTTP协议的，他们都解决了RMI所头疼的防火墙渗透问题。但是当传递过来的RPC消息中包含序列化对象时，RMI就完胜Hessian和Burlap了。因为Hessian和Burlap都采用私有的序列化机制，如果数据模型非常复杂，那么Hessian和Burlap的序列化模型可能无法胜任。

二、Hession开发步骤

1、编写服务接口

 package com.cnblogs.javalouvre.service;

 public interface GreetService {

     String sayHello(String name);

 }

2、编写服务实现类，须继承自com.caucho.hessian.server.HessianServlet

 package com.cnblogs.javalouvre.service;

 import com.caucho.hessian.server.HessianServlet;

 public class GreetServiceImpl extends HessianServlet implements GreetService {

     private static final long serialVersionUID = 1880738686281295739L;

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

 }

3、配置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>HessianServlet</servlet-name>
    <servlet-class>com.caucho.hessian.server.HessianServlet</servlet-class>
     <init-param>
       <param-name>home-class</param-name>
       <param-value>com.cnblogs.javalouvre.service.GreetServiceImpl</param-value>
     </init-param>
     <init-param>
       <param-name>home-api</param-name>
       <param-value>com.cnblogs.javalouvre.service.GreetService</param-value>
     </init-param>
     <load-on-startup>1</load-on-startup>
   </servlet>

   <servlet-mapping>
     <servlet-name>HessianServlet</servlet-name>
     <url-pattern>/GreetService</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>

4、测试客户端

 package com.cnblogs.javalouvre.client;

 import java.net.MalformedURLException;

 import com.caucho.hessian.client.HessianProxyFactory;
 import com.cnblogs.javalouvre.service.GreetService;

 public class Client {

     public static void main(String[] args) {
         String url = "http://10.108.1.138:8080/Hessian/GreetService";

         try {
             GreetService service = (GreetService) (new HessianProxyFactory()).create(GreetService.class, url);
             System.out.println(service.sayHello("Jobs"));
         } catch (MalformedURLException e) {
             e.printStackTrace();
         }
     }

 }

三、Burlap开发步骤

1、编写服务接口(同Hessian示例的接口)
    2、编写服务实现类，须继承自com.caucho.burlap.server.BurlapServlet

 package com.cnblogs.javalouvre.service;

 import com.caucho.burlap.server.BurlapServlet;

 public class GreetServiceImpl extends BurlapServlet implements GreetService {

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

 }

3、配置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>GreetService</servlet-name>
    <servlet-class>com.cnblogs.javalouvre.service.GreetServiceImpl</servlet-class>
     <load-on-startup>1</load-on-startup>
   </servlet>

   <servlet-mapping>
     <servlet-name>GreetService</servlet-name>
     <url-pattern>/GreetService</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>

4、测试客户端

 package com.cnblogs.javalouvre.client;

 import java.net.MalformedURLException;

 import com.caucho.burlap.client.BurlapProxyFactory;
 import com.cnblogs.javalouvre.service.GreetService;

 public class Client {

     public static void main(String[] args) {
         String url = "http://10.108.1.138:8080/Burlap/GreetService";

         try {
             GreetService service = (GreetService) (new BurlapProxyFactory()).create(GreetService.class, url);
             System.out.println(service.sayHello("Jobs"));
         } catch (MalformedURLException e) {
             e.printStackTrace();
         }
     }

 }