本项目基于Spring平台，整合websocket协议，实现一个简易web聊天室的功能

package boot.spring.service; import java.io.IOException; import java.util.Date; import java.util.concurrent.ConcurrentHashMap; import java.util.concurrent.atomic.AtomicInteger; 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; import org.springframework.stereotype.Component; import com.alibaba.fastjson.JSON; import boot.spring.po.Message; @ServerEndpoint("/webSocket/{username}") @Component public class WebSocketServer { //静态变量，用来记录当前在线连接数。应该把它设计成线程安全的。 private static AtomicInteger onlineNum = new AtomicInteger(); //concurrent包的线程安全Set，用来存放每个客户端对应的WebSocketServer对象。 private static ConcurrentHashMap<String, Session> sessionPools = new ConcurrentHashMap<>(); //发送消息 public void sendMessage(Session session, String message) throws IOException { if(session != null){ synchronized (session) { System.out.println("发送数据：" + message); session.getBasicRemote().sendText(message); } } } //给指定用户发送信息 public void sendInfo(String userName, String message){ Session session = sessionPools.get(userName); try { sendMessage(session, message); }catch (Exception e){ e.printStackTrace(); } } // 群发消息 public void broadcast(String message){ for (Session session: sessionPools.values()) { try { sendMessage(session, message); } catch(Exception e){ e.printStackTrace(); continue; } } } //建立连接成功调用 @OnOpen public void onOpen(Session session, @PathParam(value = "username") String userName){ sessionPools.put(userName, session); addOnlineCount(); System.out.println(userName + "加入webSocket！当前人数为" + onlineNum); // 广播上线消息 Message msg = new Message(); msg.setDate(new Date()); msg.setTo("0"); msg.setText(userName); broadcast(JSON.toJSONString(msg,true)); } //关闭连接时调用 @OnClose public void onClose(@PathParam(value = "username") String userName){ sessionPools.remove(userName); subOnlineCount(); System.out.println(userName + "断开webSocket连接！当前人数为" + onlineNum); // 广播下线消息 Message msg = new Message(); msg.setDate(new Date()); msg.setTo("-2"); msg.setText(userName); broadcast(JSON.toJSONString(msg,true)); } //收到客户端信息后，根据接收人的username把消息推下去或者群发 // to=-1群发消息 @OnMessage public void onMessage(String message) throws IOException{ System.out.println("server get" + message); Message msg=JSON.parseObject(message, Message.class); msg.setDate(new Date()); if (msg.getTo().equals("-1")) { broadcast(JSON.toJSONString(msg,true)); } else { sendInfo(msg.getTo(), JSON.toJSONString(msg,true)); } } //错误时调用 @OnError public void onError(Session session, Throwable throwable){ System.out.println("发生错误"); throwable.printStackTrace(); } public static void addOnlineCount(){ onlineNum.incrementAndGet(); } public static void subOnlineCount() { onlineNum.decrementAndGet(); } public static AtomicInteger getOnlineNumber() { return onlineNum; } public static ConcurrentHashMap<String, Session> getSessionPools() { return sessionPools; } }