According to Wikipedia, Hessian is a binary web service protocol that makes web services usable without requiring a large framework, and without learning a new set 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.
From what i’ve tested, perhaps it is somekind of light version of remote EJB3 because i dont have to include so many libraries like EJB3. Altough EJB3 and Hessian are not apple-to-apple comparable, because both arent using the same messaging protocol. EJB3 use RMI-IIOP while Hessian use WebService.
So let’s start with the code. First, for the server part (im using tomcat), create a web project on Netbeans 6.9 and creating a simple interface class,
package com.edw.service;
public interface HelloService {
String sayHelloTo(String target);
}
after that, i create a simple servlet which implements HelloService interface,
package com.edw.servlet;
import com.caucho.hessian.server.HessianServlet;
import com.edw.service.HelloService;
public class HelloServlet extends HessianServlet implements HelloService {
public String sayHelloTo(String target) {
return "hello "+target+", have a nice day";
}
}
dont forget to register your servlet to 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>HelloServlet</servlet-name>
<servlet-class>com.edw.servlet.HelloServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>HelloServlet</servlet-name>
<url-pattern>/HelloServlet</url-pattern>
</servlet-mapping>
<session-config>
<session-timeout>
30
</session-timeout>
</session-config>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
next, is creating the client application. I start with a simple java netbeans project, a main class and an interface, i copied the exact copy of HelloService and then put it on my client project,
package com.edw.service;
public interface HelloService {
String sayHelloTo(String target);
}
and my main class
package com.edw.main;
import com.caucho.hessian.client.HessianProxyFactory;
import com.edw.service.HelloService;
public class Main {
String url = "http://localhost:809/HessianServer/HelloServlet";
HessianProxyFactory factory = new HessianProxyFactory();
public Main() {
}
private void doTest() {
try {
HelloService hello = (HelloService) factory.create(HelloService.class, url);
System.out.println(hello.sayHelloTo("si pepe"));
} catch (Exception e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
Main main = new Main();
main.doTest();
}
}
here is the screenshot of my project
This is what the messaging looks like
another good competitor for Spring Http Invoker.
Have fun 
