hessian应用示例

因为公司的项目远程调用采用的是hessian，故抽时间了解了下hessian，自己也写了一个应用实例，以便加深对hessian的理解。

Hessian是一个轻量级的remoting onhttp工具，使用简单的方法提供了RMI的功能。 相比WebService，Hessian更简单、快捷。采用的是二进制RPC协议，因为采用的是二进制协议，所以它很适合于发送二进制数据。

在进行基于Hessian的项目开发时，应当注意以下几点：

JAVA服务器端必须具备以下几点：

·包含Hessian的jar包

·设计一个接口，用来给客户端调用

·实现该接口的功能

·配置web.xml，配好相应的servlet

·对象必须实现Serializable 接口

·对于复杂对象可以使用Map的方法传递

客户端必须具备以下几点：

·java客户端包含Hessian.jar的包。

·具有和服务器端结构一样的接口。包括命名空间都最好一样

·利用HessianProxyFactory调用远程接口。

以下是一个关于hessian应用的示例程序。

示例背景：

由于本人所在公司正在编码直播室方面的项目，故以下源码中用LiveRoom.java类为直播室的类。User.java类为用户类。直播室和用户之间为一对多的关系。即一个直播室里面有多个用户。本示例将实现对直播室的增删改查功能

我们先写服务端

服务端，即提供服务的一端（废话，呵呵），需要定义接口，并提供接口实现。

首先，定义两个类LiveRoom和User,并且两个类都要实现Serializable 接口

package org.study.hessian.domain;

import java.io.Serializable;

import java.util.ArrayList;

import java.util.List;

public class LiveRoom implements Serializable,Comparable<LiveRoom>{

private static final long serialVersionUID = -3219121209937741843L;

private int roomId;

private String roomName;

public List<User> users = new ArrayList<User>();

public LiveRoom(int roomId, String roomName) {

super();

this.roomId = roomId;

this.roomName = roomName;

}

public LiveRoom() {

super();

}

public int getRoomId() {

return roomId;

}

public void setRoomId(int roomId) {

this.roomId = roomId;

}

public String getRoomName() {

return roomName;

}

public void setRoomName(String roomName) {

this.roomName = roomName;

}

public int compareTo(LiveRoom o) {

if(this.getRoomId() > o.getRoomId()){

return 1;

}

else if(this.getRoomId() < o.getRoomId()){

return -1;

}

else

{

return 0;

}

}

}

package org.study.hessian.domain;

import java.io.Serializable;

import java.util.Date;

public class User implements Serializable{

private int userId;

private String userName;

private Date birth;

public int getUserId() {

return userId;

}

public void setUserId(int userId) {

this.userId = userId;

}

public String getUserName() {

return userName;

}

public void setUserName(String userName) {

this.userName = userName;

}

public Date getBirth() {

return birth;

}

public void setBirth(Date birth) {

this.birth = birth;

}

}

然后定义接口

package org.study.hessian.service;

import java.util.List;

import org.study.hessian.domain.LiveRoom;

public interface LiveRoomService {

public abstract void addRoom(LiveRoom room);

public abstract void delRoom(int roomId);

public abstract void updateRoom(LiveRoom room);

public abstract LiveRoom getRoomById(int roomId);

public abstract List<LiveRoom> getAllRoom();

}

接口的实现

package org.study.hessian.service.impl;

import java.util.ArrayList;

import java.util.Collection;

import java.util.Collections;

import java.util.HashMap;

import java.util.Iterator;

import java.util.List;

import java.util.Map;

import org.study.hessian.domain.LiveRoom;

import org.study.hessian.service.LiveRoomService;

public class LiveRoomServiceImpl implements LiveRoomService {

public Map<Integer, LiveRoom> roomMap = new HashMap<Integer, LiveRoom>();

public void addRoom(LiveRoom room) {

roomMap.put(room.getRoomId(), room);

}

public void delRoom(int roomId) {

roomMap.remove(roomId);

}

public List<LiveRoom> getAllRoom() {

List<LiveRoom> list = new ArrayList<LiveRoom>();

Collection<LiveRoom> coll = roomMap.values();

Iterator<LiveRoom> it = coll.iterator();

while(it.hasNext()){

LiveRoom room = it.next();

list.add(room);

}

Collections.sort(list);

return list;

}

public LiveRoom getRoomById(int roomId) {

return roomMap.get(roomId);

}

public void updateRoom(LiveRoom room) {

roomMap.remove(room.getRoomId());

roomMap.put(room.getRoomId(), room);

}

}

配置web.xml，配好相应的servlet

<?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">

<welcome-file-list>

<welcome-file>index.jsp</welcome-file>

</welcome-file-list>

<servlet>

<servlet-name>liveRoom</servlet-name>

<servlet-class>

com.caucho.hessian.server.HessianServlet

</servlet-class>

<init-param>

<!-- home-class也可以写为service-class -->

<param-name>home-class</param-name>

<!-- 服务器对接口的现实，供客户端调用 -->

<param-value>

org.study.hessian.service.impl.LiveRoomServiceImpl

</param-value>

</init-param>

<init-param>

<!--home-api也可以写为api-class  -->

<param-name>home-api</param-name>

<!-- 客户端接口 -->

<param-value>org.study.hessian.service.LiveRoomService</param-value>

</init-param>

</servlet>

<servlet-mapping>

<servlet-name>liveRoom</servlet-name>

<url-pattern>/liveRoom</url-pattern>

</servlet-mapping>

</web-app>

至此，服务端的代码就写完了。

接着，我们写客户端

注：客户端需要服务端定义的两个类和定义的接口（不需要接口的实现）

客户端的调用代码如下：

package org.study.hessian;

import java.net.MalformedURLException;

import java.util.ArrayList;

import java.util.Date;

import java.util.List;

import org.study.hessian.api.LiveRoomService;

import org.study.hessian.domain.LiveRoom;

import org.study.hessian.domain.User;

import org.study.hessian.utils.PropertyFileUtil;

import com.caucho.hessian.client.HessianProxyFactory;

public class Test {

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

ClassNotFoundException {

// 远程调用地址

String url="http://localhost:8080/HessianServer/liveRoom";

System.out.println(url);

HessianProxyFactory factory = new HessianProxyFactory();

LiveRoomService liveRoomService = (LiveRoomService) factory.create(

LiveRoomService.class, url);

for (int i = 1; i < 10; i++) {

LiveRoom room = new LiveRoom();

room.setRoomId(i);

room.setRoomName("liveRoom" + i);

List<User> list = new ArrayList<User>();

for (int j = 1; j < 5; j++) {

User user = new User();

user.setUserId(j);

user.setUserName("xiongyuewen" + j);

user.setBirth(new Date());

list.add(user);

}

room.users = list;

liveRoomService.addRoom(room);

}

liveRoomService.delRoom(3);

LiveRoom room = new LiveRoom();

room.setRoomId(4);

room.setRoomName("wanglili");

room.users = null;

liveRoomService.updateRoom(room);

List<LiveRoom> listRooms = liveRoomService.getAllRoom();

if (listRooms == null) {

throw new RuntimeException("listRooms is null");

}

for (LiveRoom lr : listRooms) {

System.out.println(lr.getRoomName());

List<User> users = lr.users;

if (users == null) {

continue;

}

for (User user : users) {

System.out.println(user.getUserName() + " " + user.getBirth());

}

}

}

}