websocket链接

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;

import net.sf.json.JSONObject;

import org.apache.catalina.websocket.MessageInbound;
import org.apache.catalina.websocket.WsOutbound;

public class WebSocketMessageInbound extends MessageInbound {

	//当前连接的用户名称
	private final String user;

	public WebSocketMessageInbound(String user) {
		this.user = user;
	}

	public String getUser() {
		return this.user;
	}

	//建立连接的触发的事件
	@Override
	protected void onOpen(WsOutbound outbound) {
		// 触发连接事件，在连接池中添加连接
		JSONObject result = new JSONObject();
		result.element("type", "user_join");
		result.element("user", this.user);
		//向所有在线用户推送当前用户上线的消息
		WebSocketMessageInboundPool.sendMessage(result.toString());
		
		result = new JSONObject();
		result.element("type", "get_online_user");
		result.element("list", WebSocketMessageInboundPool.getOnlineUser());
		//向连接池添加当前的连接对象
		WebSocketMessageInboundPool.addMessageInbound(this);
		//向当前连接发送当前在线用户的列表
		WebSocketMessageInboundPool.sendMessageToUser(this.user, result.toString());
	}

	@Override
	protected void onClose(int status) {
		// 触发关闭事件，在连接池中移除连接
		WebSocketMessageInboundPool.removeMessageInbound(this);
		JSONObject result = new JSONObject();
		result.element("type", "user_leave");
		result.element("user", this.user);
		//向在线用户发送当前用户退出的消息
		WebSocketMessageInboundPool.sendMessage(result.toString());
	}

	@Override
	protected void onBinaryMessage(ByteBuffer message) throws IOException {
		throw new UnsupportedOperationException("Binary message not supported.");
	}

	//客户端发送消息到服务器时触发事件
	@Override
	protected void onTextMessage(CharBuffer message) throws IOException {
		//向所有在线用户发送消息
		WebSocketMessageInboundPool.sendMessage(message.toString());
	}
}

import java.io.IOException;
import java.nio.CharBuffer;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;

public class WebSocketMessageInboundPool {

	//保存连接的MAP容器
	private static final Map connections = new HashMap();
	
	//向连接池中添加连接
	public static void addMessageInbound(WebSocketMessageInbound inbound){
		//添加连接
		System.out.println("user : " + inbound.getUser() + " join..");
		connections.put(inbound.getUser(), inbound);
	}
	
	//获取所有的在线用户
	public static Set getOnlineUser(){
		return connections.keySet();
	}
	
	public static void removeMessageInbound(WebSocketMessageInbound inbound){
		//移除连接
		System.out.println("user : " + inbound.getUser() + " exit..");
		connections.remove(inbound.getUser());
	}
	
	public static void sendMessageToUser(String user,String message){
		try {
			//向特定的用户发送数据
			System.out.println("send message to user : " + user + " ,message content : " + message);
			WebSocketMessageInbound inbound = connections.get(user);
			if(inbound != null){
				inbound.getWsOutbound().writeTextMessage(CharBuffer.wrap(message));
			}
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
	
	//向所有的用户发送消息
	public static void sendMessage(String message){
		try {
			Set keySet = connections.keySet();
			for (String key : keySet) {
				WebSocketMessageInbound inbound = connections.get(key);
				if(inbound != null){
					System.out.println("send message to user : " + key + " ,message content : " + message);
					inbound.getWsOutbound().writeTextMessage(CharBuffer.wrap(message));
				}
			}
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
}

import javax.servlet.http.HttpServletRequest;

import org.apache.catalina.websocket.StreamInbound;

public class WebSocketMessageServlet extends org.apache.catalina.websocket.WebSocketServlet {

	private static final long serialVersionUID = 1L;
	
	public static int ONLINE_USER_COUNT	= 1;
	
	public String getUser(HttpServletRequest request){
		return (String) request.getSession().getAttribute("user");
	}

	//跟平常Servlet不同的是，需要实现createWebSocketInbound，在这里初始化自定义的WebSocket连接对象
    @Override
    protected StreamInbound createWebSocketInbound(String subProtocol,HttpServletRequest request) {
        return new WebSocketMessageInbound(this.getUser(request));
    }
}