JavaWeb–使用Websocket实现在线聊天功能

package websocket.chat;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import javax.servlet.http.HttpSession;
import javax.websocket.EndpointConfig;
import javax.websocket.OnClose;
import javax.websocket.OnError;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import javax.websocket.server.ServerEndpoint;

import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;

import com.chat.common.HTMLFilter;
import com.chat.controller.UserDAOImpl;
import com.chat.entity.User;

@ServerEndpoint(value = "/index.jsp",configurator=GetHttpSessionConfigurator.class)
public class ChatAnnotation {
	private static final Log log = LogFactory.getLog(ChatAnnotation.class);
    private static final Map<String, ChatAnnotation> connection = new HashMap<String, ChatAnnotation>();
    private String userId;
    private String nickname;
    private Session session;
    public ChatAnnotation() {
    }
    @OnOpen
    public void start(Session session,EndpointConfig config) {
      //获取HttpSession对象
       HttpSession httpSession = (HttpSession) config.getUserProperties().get(HttpSession.class.getName());
       User user = (User)httpSession.getAttribute("user");
       String uid = user.getId();
       this.nickname = user.getUsername();
       this.userId = uid;
       
       this.session = session;
        /*判断链接是否已经在链接队列中，存在就不加*/
       if(!connection.containsKey(uid)){
    	   connection.put(uid, this);
    	   String message = "* 你已经链接";
    	   toConfirmFriend(message,userId);
       }
    }
    @OnClose
    public void end() {
        connection.remove(this.userId);
    }
    @OnMessage
    public void incoming(String message){
    	String[] all = message.split("-");
    	//要接收消息好友的ID
    	String uid = all[1];
    	//判断好友的连接是否存在，不存在就提示好友掉线
    	if(connection.containsKey(uid)){
    		 String filteredMessage = String.format("%s: %s",
    	                nickname, HTMLFilter.filter(all[0].toString()));
    	        sendCommonRecord(filteredMessage,uid,this.userId);
    	}else{
    		ChatAnnotation client = connection.get(uid);
    		 String mes = String.format("* %s %s",
                     client.nickname, "已经掉线！");
    		//将掉线信息发给自己
    		 toConfirmFriend(mes,this.userId);
    	}
    }
    @OnError
    public void onError(Throwable t) throws Throwable {
        log.error("Chat Error: " + t.toString(), t);
    }
    //发送给指定的好友
    private static void toConfirmFriend(String msg,String uid) {
        ChatAnnotation client = connection.get(uid);
        try {
            synchronized (client) {
                client.session.getBasicRemote().sendText(msg);
            }
        } catch (IOException e) {
            log.debug("Chat Error: Failed to send message to "+client.nickname, e);
            try {
                client.session.close();
            } catch (IOException e1) {
                // Ignore
            }
        }
    }
    //给聊天的双发发共同消息
    private static void sendCommonRecord(String msg,String sid,String gid) {
        ChatAnnotation client_send = connection.get(sid);
        ChatAnnotation client_get = connection.get(gid);
        try {
            synchronized (client_send) {
            	client_send.session.getBasicRemote().sendText(msg);
            }
            //将这条聊天记录保存在数据库
            UserDAOImpl userDAOImpl = new UserDAOImpl();
            userDAOImpl.saveCharRecord(msg, sid, gid);
        } catch (IOException e) {
            log.debug("Chat Error: Failed to send message to "+client_send.nickname, e);
            connection.remove(sid);
            try {
            	client_send.session.close();
            }catch (IOException e1) {
                // Ignore
            }
        }
        try {
            synchronized (client_get) {
            	client_get.session.getBasicRemote().sendText(msg);
            }
        } catch (IOException e) {
            log.debug("Chat Error: Failed to send message to "+client_get.nickname, e);
            connection.remove(gid);
            try {
            	client_get.session.close();
            } catch (IOException e1) {
                // Ignore
            }
        }
    }
}