基于二进制RPC协议法的轻量级远程调用框架 ---- Hessian

使用Java创建Hessian服务有四个步骤:

1、创建Java接口作为公共API (client和server端创建一个相同的借口)

2、使用HessianProxyFactory创建一个客户端 (client端)

3、创建服务实现类，继承HessianServlet (server端)

4、在servlet引擎中配置服务。 (server端)

代码示例：

server端：

package com.lin.hessian.service;
public interface Basic {
    public String sayHello();
}

package com.lin.hessian.service;
import com.caucho.hessian.server.HessianServlet;
public class LinyService extends HessianServlet implements Basic{
    private String message = "wowwowowowowow";
    @Override
    public String sayHello() {
        return message;
    }
}

<?xml version="1.0" encoding="UTF-8"?>

<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
  <display-name>HessianWeb</display-name>
  <servlet>     
        <servlet-name>hello</servlet-name>     
        <servlet-class>com.caucho.hessian.server.HessianServlet</servlet-class>     
        <init-param>     
            <param-name>home-class</param-name>     
            <param-value>com.lin.hessian.service.BasicService</param-value>     
        </init-param>     
        <init-param>     
            <param-name>home-api</param-name>
            <param-value>com.lin.hessian.service.Basic</param-value>     
        </init-param>     
    </servlet>
    
    <servlet-mapping>     
        <servlet-name>hello</servlet-name>     
        <url-pattern>/hello</url-pattern>     
    </servlet-mapping>

    <servlet>     
        <servlet-name>liny</servlet-name>     
        <servlet-class>com.lin.hessian.service.LinyService</servlet-class>         
    </servlet>
    
    <servlet-mapping>     
        <servlet-name>liny</servlet-name>
        <url-pattern>/liny</url-pattern>     
    </servlet-mapping>
</web-app>

client端：

package com.liny.hessian.service;
public interface Basic {
    public String sayHello();
}

package com.lin.hessian.client;
import java.net.MalformedURLException;
import com.caucho.hessian.client.HessianProxyFactory;
import com.liny.hessian.service.Basic;
public class HessianClient {
    public static void main(String[] args) throws MalformedURLException{
　　　　 //String url = "http://localhost:8080/HessianWeb/hello";
        String url = "http://localhost:8080/HessianWeb/liny";
        HessianProxyFactory factory = new HessianProxyFactory();
        Basic basic = (Basic)factory.create(Basic.class, url);
        System.out.println(basic.sayHello());
    }
}

client端要定义一个同server端一模一样的接口Basic，然后通过HessianProxyFactory获得代理，并调用远程服务的方法。