Smack

昨晚被Smack的example郁闷了，误以为MessageListener是用来返回对方的回复信息，今天终于搞明白了。

Smack是XMPP的一个Java客户端library，可以用来实现Instance Message Tool(Spark、Sparkweb)。服务器端也有相应的的实现，叫Op

enfire，当然，这里只对这两个XMPP的实现讨论，还有很多其他开源实现。顺便提一下，和Smack对应的有个XIFF的Flash客户端实现。

贴一个例子，假设首先启动了Openfire服务器，用Spark客户端登录了某个账户prc，然后在代码中用另一个用户登录，并进行交谈。

效果图：

package org.prc;

import org.jivesoftware.smack.Chat;
import org.jivesoftware.smack.ChatManager;
import org.jivesoftware.smack.ConnectionConfiguration;
import org.jivesoftware.smack.MessageListener;
import org.jivesoftware.smack.PacketListener;
import org.jivesoftware.smack.XMPPConnection;
import org.jivesoftware.smack.XMPPException;
import org.jivesoftware.smack.filter.PacketFilter;
import org.jivesoftware.smack.filter.PacketTypeFilter;
import org.jivesoftware.smack.packet.Message;
import org.jivesoftware.smack.packet.Packet;

/**
 * Chat prototype using smack as client library. Server side are supported by
 * openfire.
 * 
 * @author promise
 * @date 2009-3-30
 * 
 */
public class FireChat {
 public static XMPPConnection con;
 public static Chat newChat;
 public static ChatManager chatmanager;

 public static void main(String[] args) throws InterruptedException {
  // XMPPConnection.DEBUG_ENABLED = true;
  try {
   // Create a connection to server
   ConnectionConfiguration config = new ConnectionConfiguration(
     "localhost", 5222);
   con = new XMPPConnection(config);

   // connect and login with the username and pwd on server
   con.connect();
   con.login("promise", "promise");
   System.out.println("Authenticated = " + con.isAuthenticated());

   // add a listener to receive all messages
   addListener();

   chatmanager = con.getChatManager();
   newChat = chatmanager.createChat("prc@fantasy-promise/spark",
     new MessageListener() {
      public void processMessage(Chat chat, Message message) {
       System.out.println("I'm sending: "
         + message.getBody());
      }
     });
   newChat.sendMessage("hi");
  } catch (XMPPException e) {
   e.printStackTrace();
  } finally {
   Thread.sleep(3600000);
   con.disconnect();
  }
 }

 private static void addListener() {
  // just need Messages :)
  PacketFilter filterMessage = new PacketTypeFilter(Message.class);

  PacketListener myListener = new PacketListener() {
   public void processPacket(Packet packet) {
    System.out.println("From: " + packet.getFrom() + "\n");
    System.out.println("Body: " + ((Message) packet).getBody());
    // when receiving prc's Message, just say something else again
    // and again, robot :)
    try {
     newChat.sendMessage("hi again :)");
    } catch (XMPPException e) {
     e.printStackTrace();
    }
   }
  };
  // register the listener to the connection
  con.addPacketListener(myListener, filterMessage);
 }
}