baidu百科這樣介紹它：
Hessian是一個輕量級的remoting on http工具，使用簡單的方法提供了RMI的功能. 相比WebService，Hessian更簡單、快捷。采用的是二進制RPC協議，因為采用的是二進制協議，所以它很適合于發送二進制數據.
開元百科這樣介紹它：
Hessian是Caucho開發的一種二進制Web Service協議。采取Apache許可協議.
The Hessian binary web service protocol makes web services usable without requiring a large framework, and without learning yet another alphabet soup of protocols. Because it is a binary protocol, it is well-suited to sending binary data without any need to extend the protocol with attachments.
Hessian是一個精心打造的Web Service實現，它支持Java、C#、Ruby、PHP和Python，又新增了ActionScript。使用Adobe Flash和Flex的RIA開發者們在需要集成業務服務的時候，Hessian應該是一個不錯的選擇。
既然都它這么神奇，那么我們就又要去認識下這位新朋友。
項目主頁：
http://hessian.caucho.com/
建議大家仔細認真閱讀下官方網站。
還是先從helloworld著手。
它只需要一個jar包即可
去官方下載適用于java環境下的jar包支持
hessian-4.0.7.jar hessian-4.0.7-src.jar
創建web工程。
編寫接口：
package com.hessian.demo.inf;
public interface HelloWorld {
public String sayHelloWorld(String name);
}
編寫實現類：
package com.hessian.demo.impl;
import com.hessian.demo.inf.HelloWorld;
public class HelloWorldImpl implements HelloWorld {
public String sayHelloWorld(String name) {
return "Hello ,"+name+"Welcome to use hessian ! ";
}
}
配置web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5"
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">
<servlet>
<servlet-name>helloworld</servlet-name>
<servlet-class>com.caucho.hessian.server.HessianServlet</servlet-class>
<init-param>
<!-- 此處hom-api為固定寫法,為HessianServlet中定義的參數詳細可參考HessianServlet -->
<!-- 其值為接口的類長名即 包名+類名 -->
<param-name>home-api</param-name>
<param-value>com.hessian.demo.inf.HelloWorld</param-value>
</init-param>
<init-param>
<!-- 此處hom-class為固定寫法,為HessianServlet中定義的參數詳細可參考HessianServlet -->
<!-- 其值為實現類的類長名即 包名+類名 -->
<param-name>home-class</param-name>
<param-value>com.hessian.demo.impl.HelloWorldImpl</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>helloworld</servlet-name>
<url-pattern>/helloworld</url-pattern>
</servlet-mapping>
</web-app>
此處web.xml中配置的初始化參數具體可參考HessianServlet的init()方法
public void init(ServletConfig config)
throws ServletException
{
super.init(config);
try {
if (_homeImpl != null) {
}
else if (getInitParameter("home-class") != null) {
String className = getInitParameter("home-class");
Class homeClass = loadClass(className);
_homeImpl = homeClass.newInstance();
init(_homeImpl);
}
else if (getInitParameter("service-class") != null) {
String className = getInitParameter("service-class");
Class homeClass = loadClass(className);
_homeImpl = homeClass.newInstance();
init(_homeImpl);
}
else {
if (getClass().equals(HessianServlet.class))
throw new ServletException("server must extend HessianServlet");
_homeImpl = this;
}
if (_homeAPI != null) {
}
else if (getInitParameter("home-api") != null) {
String className = getInitParameter("home-api");
_homeAPI = loadClass(className);
}
else if (getInitParameter("api-class") != null) {
String className = getInitParameter("api-class");
_homeAPI = loadClass(className);
}
else if (_homeImpl != null) {
_homeAPI = findRemoteAPI(_homeImpl.getClass());
if (_homeAPI == null)
_homeAPI = _homeImpl.getClass();
}
if (_objectImpl != null) {
}
else if (getInitParameter("object-class") != null) {
String className = getInitParameter("object-class");
Class objectClass = loadClass(className);
_objectImpl = objectClass.newInstance();
init(_objectImpl);
}
if (_objectAPI != null) {
}
else if (getInitParameter("object-api") != null) {
String className = getInitParameter("object-api");
_objectAPI = loadClass(className);
}
else if (_objectImpl != null)
_objectAPI = _objectImpl.getClass();
_homeSkeleton = new HessianSkeleton(_homeImpl, _homeAPI);
if (_objectAPI != null)
_homeSkeleton.setObjectClass(_objectAPI);
if (_objectImpl != null) {
_objectSkeleton = new HessianSkeleton(_objectImpl, _objectAPI);
_objectSkeleton.setHomeClass(_homeAPI);
}
else
_objectSkeleton = _homeSkeleton;
if ("true".equals(getInitParameter("debug")))
_isDebug = true;
if ("false".equals(getInitParameter("send-collection-type")))
setSendCollectionType(false);
} catch (ServletException e) {
throw e;
} catch (Exception e) {
throw new ServletException(e);
}
}
編寫客戶端測試代碼：
package com.hessian.demo.client;
import com.caucho.hessian.client.HessianProxyFactory;
import com.hessian.demo.inf.HelloWorld;
public class HelloWorldClient {
public static void main(String[] args) throws Exception{
//servlet的訪問路徑
String url="http://localhost:8080/hessian/helloworld";
//創建一HessianProxyFactory對象,用法與xfire很像
HessianProxyFactory proxyFactory=new HessianProxyFactory();
//獲得HelloWorld的實例,傳遞兩個參數依次為:接口.class,該servlet的訪問路徑
HelloWorld helloWorld=(HelloWorld) proxyFactory.create(HelloWorld.class, url);
System.out.println(helloWorld.sayHelloWorld("張三"));
}
}
效果圖：
