1、通过WebSocketServlet来实现

import java.io.IOException;import java.io.UnsupportedEncodingException;import java.nio.ByteBuffer;import java.nio.CharBuffer;import java.text.SimpleDateFormat;import java.util.Date;import java.util.HashMap;import java.util.Map;import java.util.Set;import javax.servlet.http.HttpServletRequest;import org.apache.catalina.websocket.MessageInbound;import org.apache.catalina.websocket.StreamInbound;import org.apache.catalina.websocket.WebSocketServlet;import org.apache.catalina.websocket.WsOutbound;public class ChatWebSocketServlet extends WebSocketServlet {    /**     *     */    private static final long serialVersionUID = 911879078000755859L;    //private final Map
     
       map = new HashMap
      
       ();    private final Map
       
         users = new HashMap
        
         ();        @Override    protected StreamInbound createWebSocketInbound(String arg0, HttpServletRequest request)    {        String username = null;        try {            username = request.getParameter("username");            System.out.println(username);            if(username != null){                username = new String(username.getBytes("ISO8859_1"),"UTF-8");            }        } catch (Exception e) {            // TODO Auto-generated catch block            e.printStackTrace();        }        System.out.println(username+" 请求连接：");        return new ChatMessageInbound(username);    }    class ChatMessageInbound extends MessageInbound {                private String userName = "user";                public ChatMessageInbound(String userName) {                this.userName = userName;        }        @Override        protected void onOpen(WsOutbound outbound) {            users.put(userName, outbound);            System.out.println(userName+"上线了,总共"+users.size()+"人在线");            super.onOpen(outbound);        }        @Override        protected void onClose(int status) {            users.remove(userName);            System.out.println("下线："+userName);            super.onClose(status);        }        @Override        protected void onBinaryMessage(ByteBuffer buffer) throws IOException {            // TODO Auto-generated method stub        }        @Override        protected void onTextMessage(CharBuffer buffer) throws IOException {            String msg = buffer.toString();            System.out.println(userName+"："+msg);            Date date = new Date();            SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss");            msg = userName+" " + sdf.format(date)+":\n" + msg;            broadcast(msg);        }        private void broadcast(String msg) {            Set
         
           set = users.keySet();            for (String name : set)            {                    WsOutbound outbound = users.get(name);                    CharBuffer buffer = CharBuffer.wrap(msg);                    try {                            outbound.writeTextMessage(buffer);                            outbound.flush();                    } catch (Exception e) {                        e.printStackTrace();                    }                System.out.println(name+"----");                            }        }    }}
         
        
       
      
     

2、通过@ServerEndpoint注解

import java.io.IOException;import java.util.Set;import java.util.concurrent.CopyOnWriteArraySet;import javax.websocket.OnClose;import javax.websocket.OnError;import javax.websocket.OnMessage;import javax.websocket.OnOpen;import javax.websocket.Session;import javax.websocket.server.PathParam;import javax.websocket.server.ServerEndpoint;@ServerEndpoint(value = "/ws/chat/{nickName}")public class Chat {    /**     * 连接对象集合     */    private static final Set
     
       connections = new CopyOnWriteArraySet
      
       ();    private String nickName;    /**     * WebSocket Session     */    private Session session;    public Chat() {    }    /**     * 打开连接     *      * @param session     * @param nickName     */    @OnOpen    public void onOpen(Session session,            @PathParam(value = "nickName") String nickName) {        this.session = session;        this.nickName = nickName;        connections.add(this);        String message = String.format("System> %s %s", this.nickName,                " has joined.");        Chat.broadCast(message);        System.out.println(message);    }    /**     * 关闭连接     */    @OnClose    public void onClose() {        connections.remove(this);        String message = String.format("System> %s, %s", this.nickName,                " has disconnection.");        Chat.broadCast(message);        System.out.println(message);    }    /**     * 接收信息     *      * @param message     * @param nickName     */    @OnMessage    public void onMessage(String message,            @PathParam(value = "nickName") String nickName) {        Chat.broadCast(nickName + ">" + message);        System.out.println(message);    }    /**     * 错误信息响应     *      * @param throwable     */    @OnError    public void onError(Throwable throwable) {        System.out.println(throwable.getMessage());    }    /**     * 发送或广播信息     *      * @param message     */    private static void broadCast(String message) {        for (Chat chat : connections) {            try {                synchronized (chat) {                    chat.session.getBasicRemote().sendText(message);                }            } catch (IOException e) {                connections.remove(chat);                try {                    chat.session.close();                } catch (IOException e1) {                }                Chat.broadCast(String.format("System> %s %s", chat.nickName,                        " has bean disconnection."));                System.out.println(String.format("System> %s %s", chat.nickName,                        " has bean disconnection."));            }        }    }}
      
     

3、android

package com.example.test;import android.app.Activity;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.EditText;import android.widget.Toast;import de.tavendo.autobahn.WebSocketConnection;import de.tavendo.autobahn.WebSocketConnectionHandler;import de.tavendo.autobahn.WebSocketException;public class MainActivity extends Activity {    final WebSocketConnection wsc = new WebSocketConnection();    private EditText edt;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        edt = (EditText) findViewById(R.id.edt1);        findViewById(R.id.btn1).setOnClickListener(new OnClickListener() {            @Override            public void onClick(View v) {                if (wsc.isConnected()) {                    wsc.sendTextMessage(edt.getText().toString());                } else {                    Toast.makeText(getApplicationContext(), "请先加入",                            Toast.LENGTH_SHORT).show();                }            }        });        // System.out.println("websocket///");        findViewById(R.id.btn2).setOnClickListener(new OnClickListener() {            @Override            public void onClick(View v) {                try {                    //"ws://192.168.1.106:9090/websocket01/chat.ws?username=server11"                    String url = "ws://192.168.1.106:8080/websocket01/ws/chat/server11";                    wsc.connect(url,                            new WebSocketConnectionHandler() {                                @Override                                public void onBinaryMessage(byte[] payload) {                                    System.out.println("onBinaryMessage size="                                            + payload.length);                                }                                @Override                                public void onClose(int code, String reason) {                                    System.out.println("onClose reason="                                            + reason);                                }                                @Override                                public void onOpen() {                                    System.out.println("onOpen");                                    wsc.sendTextMessage("Hello!");                                    // wsc.disconnect();                                }                                @Override                                public void onRawTextMessage(byte[] payload) {                                    System.out.println("onRawTextMessage size="                                            + payload.length);                                                                    }                                @Override                                public void onTextMessage(String payload) {                                    System.out.println("onTextMessage"                                            + payload);                                    edt.setText(payload);                                }                            });                } catch (WebSocketException e) {                    // TODO Auto-generated catch block                    e.printStackTrace();                }            }        });    }    @Override    protected void onStop() {        wsc.disconnect();        super.onStop();    }}

来自网络，稍加修改。