feat: 实时在线用户统计

src/main/java/com/youlai/system/service/impl/WebsocketServiceImpl.java

@@ -0,0 +1,44 @@
+package com.youlai.system.service.impl;
+
+import com.youlai.system.service.WebsocketService;
+import groovy.lang.Lazy;
+import lombok.RequiredArgsConstructor;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.messaging.simp.SimpMessagingTemplate;
+import org.springframework.scheduling.annotation.Scheduled;
+import org.springframework.stereotype.Service;
+
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+
+@Service
+public class WebsocketServiceImpl implements WebsocketService {
+
+    @Lazy
+    @Autowired
+    private  SimpMessagingTemplate messagingTemplate;
+
+    private static final Set<String> onlineUsers = ConcurrentHashMap.newKeySet();
+
+    @Override
+    public void addUser(String username) {
+        onlineUsers.add(username);
+    }
+
+    @Override
+    public void removeUser(String username) {
+        onlineUsers.remove(username);
+    }
+
+    @Override
+    public int getOnlineUserCount() {
+        return onlineUsers.size();
+    }
+
+    @Scheduled(fixedRate = 5000)
+    public void sendOnlineUserCount() {
+        int onlineUserCount = this.getOnlineUserCount();
+        messagingTemplate.convertAndSend("/topic/onlineUserCount", onlineUserCount);
+    }
+
+}