体验Hessian

Hessian RPC 实现

最新推荐文章于 2025-08-03 11:39:45 发布

原创最新推荐文章于 2025-08-03 11:39:45 发布 · 1k 阅读

1 ·

CC 4.0 BY-SA版权

本文介绍了一个使用 Hessian 实现的远程过程调用 (RPC) 示例。通过配置 web.xml 和编写 BasicAPI 接口及其实现类 BasicService，实现字符串问候、列表和映射转换的功能。客户端通过 HessianProxyFactory 发起请求并展示结果。

体验了一把Hessian。

工程目录：

服务端：

web.xml中追加如下内容

<servlet-name>Hessian Service</servlet-name>

<servlet-class>com.caucho.hessian.server.HessianServlet</servlet-class>

<init-param>

<param-name>service-class</param-name>

<param-value>com.mytest.hessian.BasicService</param-value>

</init-param>

</servlet>

<servlet-mapping>

<servlet-name>Hessian Service</servlet-name>

<url-pattern>/basic</url-pattern>

</servlet-mapping>

BasicAPI.java

package com.mytest.hessian;

import java.util.List;

import java.util.Map;

public interface BasicAPI {

public String hello();

public Map getMap(Map m);

public List getList(List li);

}

BasicService.java

package com.mytest.hessian;

import java.util.ArrayList;

import java.util.Iterator;

import java.util.List;

import java.util.Map;

import java.util.Set;

import java.util.TreeMap;

import java.util.Map.Entry;

import com.caucho.hessian.server.HessianServlet;

public class BasicService extends HessianServlet implements BasicAPI {

private String _greeting = "Hello, world";

public void setGreeting(String greeting) {

_greeting = greeting;

}

public String hello() {

return _greeting;

}

//[1, 2, a, 5] => [*, **, null, *****]

@Override

public List getList(List li) {

List r = new ArrayList();

for(int i=0; i<li.size(); i++) {

Object o = li.get(i);

if(o instanceof Integer) {

int n = (Integer)o;

r.add(buildStar(n));

}else {

r.add(null);

continue;

}

return r;

}

private String buildStar(int n) {

StringBuilder sb = new StringBuilder(10);

for(int i=0; i<n; i++) {

sb.append("*");

}

return sb.toString();

}

//{a=>1, b=>2, c=>'beta'} => {a => '*', b => '**', c => null}

@Override

public Map getMap(Map m) {

Map r = new TreeMap();

Set set = m.entrySet();

Iterator iter = set.iterator();

while(iter.hasNext()) {

Entry entry = (Entry) iter.next();

String k = (String)entry.getKey();

Object o = entry.getValue();

if(o instanceof Integer) {

r.put(k, buildStar((Integer)o));

}else {

r.put(k, null);

}

return r;

}

客户端：

BasicAPI.java

同上。

Client.java

import java.net.MalformedURLException;

import java.util.ArrayList;

import java.util.List;

import java.util.Map;

import java.util.TreeMap;

import com.caucho.hessian.client.HessianProxyFactory;

import com.mytest.hessian.BasicAPI;

public class Client {

public static void main(String[] args) throws MalformedURLException{

String url = "http://localhost:8080/HessianService/basic";

HessianProxyFactory factory = new HessianProxyFactory();

BasicAPI basic = (BasicAPI) factory.create(BasicAPI.class, url);

// hello world

System.out.println("hello: " + basic.hello());

//[1, 2, a, 5] => [*, **, null, *****]

//getList

List li = basic.getList(getInputList());

System.out.println(li);

//{a=>1, b=>2, c=>'beta'} => {a => '*', b => '**', c => null}

//getMap

Map m = basic.getMap(getInputMap());

System.out.println(m);

}

@SuppressWarnings("unchecked")

public static List getInputList() {

List inputList = new ArrayList();

inputList.add(1);

inputList.add(2);

inputList.add("a");

inputList.add(5);

return inputList;

}

@SuppressWarnings("unchecked")

public static Map getInputMap() {

Map inputMap = new TreeMap();

inputMap.put("a", 1);

inputMap.put("b", 2);

inputMap.put("c", "beta");

return inputMap;

}

运行Client,输出如下信息：

hello: Hello, world

[*, **, null, *****]

{a=*, b=**, c=null}