JGroups实现聊天小程序

package com.lei.jgoups; import java.io.BufferedReader;import java.io.DataInputStream;import java.io.DataOutputStream;import java.io.InputStream;import java.io.InputStreamReader;import java.io.OutputStream;import java.util.LinkedList;import java.util.List; import org.jgroups.JChannel;import org.jgroups.Message;import org.jgroups.ReceiverAdapter;import org.jgroups.View;import org.jgroups.util.Util; public class SimpleChat extends ReceiverAdapter{ JChannel channel; String user_name=System.getProperty("user.name", "n/a"); final List<String> state=new LinkedList<String>(); public static void main(String[] args) throws Exception { new SimpleChat().start(); } private void start() throws Exception { channel=new JChannel();// 使用默认的配置, udp.xml【YBXIANG:】该文件位于jgroups-x.y.z.Final.jar中。 channel.setReceiver(this);//注册一个 Receiver 来接收消息并查看变化 channel.connect("ChatCluster"); channel.getState(null, 10000); eventLoop(); channel.close(); }  private void eventLoop() { BufferedReader in = new BufferedReader(new InputStreamReader(System.in)); while(true) { try { System.out.print(">");  System.out.flush(); String line=in.readLine().toLowerCase(); if(line.startsWith("quit") || line.startsWith("exit"))  break; line="[" + user_name + "] " + line; Message msg=new Message(null, line); channel.send(msg); } catch(Exception e) { } } }  //如果有节点加入后会回调此函数 public void viewAccepted(View new_view) { System.out.println("** view: " + new_view); }  //接收到消息后会调用此函数 public void receive(Message msg) { String line=msg.getSrc() + ": " + msg.getObject(); System.out.println(line); synchronized(state) {//同步调用 state.add(line); } }  //getState回调方法 public void getState(OutputStream output) throws Exception { synchronized(state) { Util.objectToStream(state, new DataOutputStream(output)); } }  // 从input stream中读取状态，然后做相应的设置： public void setState(InputStream input) throws Exception { List<String> list; list=(List<String>)Util.objectFromStream(new DataInputStream(input)); synchronized(state) { state.clear(); state.addAll(list); } System.out.println(list.size() + " messages in chat history):"); for(String str: list) { System.out.println(str); } }}