ver2: 新增 room/message/getUpdate 接口，将消息轮询优化为只轮询最新消息；登录用户每次进入聊天室默认打开最近访问的房间

chatroom/src/app/api/room/message/getUpdate/route.ts

+// src/app/api/room/message/getUpdate/route.ts
+import { NextRequest, NextResponse } from 'next/server';
+import { PrismaClient } from '@prisma/client';
+
+const prisma = new PrismaClient();
+
+export async function GET(req: NextRequest) {
+  try {
+    const { searchParams } = new URL(req.url);
+    const roomId = searchParams.get('roomId');
+    const sinceMessageId = searchParams.get('sinceMessageId');
+    
+    if (!roomId) {
+      return NextResponse.json({ 
+        code: 1, 
+        message: '缺少 roomId 参数' 
+      }, { status: 400 });
+    }
+
+    if (!sinceMessageId) {
+      return NextResponse.json({ 
+        code: 1, 
+        message: '缺少 sinceMessageId 参数' 
+      }, { status: 400 });
+    }
+
+    // 获取指定消息ID之后的所有新消息
+    const messages = await prisma.message.findMany({
+      where: { 
+        roomId: Number(roomId),
+        id: { 
+          gt: Number(sinceMessageId) // greater than - 大于指定的消息ID
+        }
+      },
+      orderBy: { createdAt: 'asc' },
+    });
+
+    const formattedMessages = messages.map(msg => ({
+      messageId: msg.id,
+      roomId: msg.roomId,
+      sender: msg.sender,
+      content: msg.content,
+      time: msg.createdAt.getTime(),
+    }));
+
+    return NextResponse.json({ 
+      code: 0, 
+      data: { messages: formattedMessages } 
+    });
+  } catch (error) {
+    console.error('获取增量消息失败:', error);
+    return NextResponse.json({ 
+      code: 1, 
+      message: '获取消息失败' 
+    }, { status: 500 });
+  }
+}
\ No newline at end of file

chatroom/src/app/chat/page.tsx

@@ -73,7 +73,6 @@ function MessageItem({ message, currentUser }: MessageItemProps) {
   );
 }
 
-// 单个房间组件
 // 登录状态组件
 function AuthStatus({ isLoggedIn, username, onLogout }: { 
   isLoggedIn: boolean; 
@@ -124,13 +123,13 @@ function PermissionAlert({ message, onClose }: { message: string; onClose: () =>
   );
 }
 
-// 单个房间组件 - 添加权限检查
+// 单个房间组件
 interface RoomEntryProps {
   room: RoomPreviewInfo;
   onClick: () => void;
   isActive: boolean;
   onDelete: () => void;
-  canDelete: boolean; // 新增：是否可以删除
+  canDelete: boolean;
 }
 
 function RoomEntry({ room, onClick, isActive, onDelete, canDelete }: RoomEntryProps) {
@@ -178,9 +177,35 @@ export default function ChatPage() {
   const [permissionAlertMessage, setPermissionAlertMessage] = useState('');
   const router = useRouter();
 
+  // 新增：消息相关状态
+  const [messages, setMessages] = useState<Message[]>([]);
+  const [lastMessageId, setLastMessageId] = useState<number>(0);
+  const [isFirstLoad, setIsFirstLoad] = useState(true);
+
   // 使用身份验证 hook
   const { isLoggedIn, username: authUsername, isLoading: authLoading, logout } = useAuth();
 
+  // v2新增：保存最后访问的房间ID到 localStorage
+  const saveLastRoom = (roomId: number | null) => {
+    if (roomId) {
+      localStorage.setItem('lastRoomId', roomId.toString());
+    } else {
+      localStorage.removeItem('lastRoomId');
+    }
+  };
+
+  // v2新增读取最后访问的房间ID
+  const getLastRoom = (): number | null => {
+    const lastRoom = localStorage.getItem('lastRoomId');
+    return lastRoom ? parseInt(lastRoom, 10) : null;
+  };
+
+  // v2新增更新 selectedRoomId 的设置函数，同时保存到 localStorage
+  const handleSelectRoom = (roomId: number | null) => {
+    setSelectedRoomId(roomId);
+    saveLastRoom(roomId);
+  };
+
   useEffect(() => {
     const saved = localStorage.getItem('nickname');
     if (!saved) {
@@ -213,18 +238,80 @@ export default function ChatPage() {
     { refreshInterval: 1000 }
   );
 
-  // 获取消息列表
+  // v2新增：房间列表加载完成后，自动选择上次访问的房间
+  useEffect(() => {
+    // 只在房间列表首次加载完成且没有选中房间时执行
+    if (roomData?.rooms && !selectedRoomId) {
+      const lastRoomId = getLastRoom();
+      
+      if (lastRoomId) {
+        // 检查上次的房间是否仍然存在
+        const roomExists = roomData.rooms.some(r => r.roomId === lastRoomId);
+        
+        if (roomExists) {
+          console.log(`自动进入上次访问的房间: ${lastRoomId}`);
+          setSelectedRoomId(lastRoomId);
+        } else {
+          // 如果上次的房间不存在了，清除记录
+          console.log('上次访问的房间已不存在');
+          localStorage.removeItem('lastRoomId');
+        }
+      }
+    }
+  }, [roomData, selectedRoomId]);
+
+
+  // v2改进：首次加载获取全部消息
   const {
-    data: messageData,
-    error: messageError,
-    isLoading: messageIsLoading,
-    mutate: refreshMessages,
+    data: initialMessages,
+    error: initialError,
+    isLoading: initialLoading
   } = useSWR<RoomMessageListRes>(
-    selectedRoomId ? `/api/room/message/list?roomId=${selectedRoomId}` : null,
+    selectedRoomId && isFirstLoad ? `/api/room/message/list?roomId=${selectedRoomId}` : null,
+    (key) => authFetch(key).then((r) => r.json().then((d: any) => d.data)),
+    { 
+      revalidateOnFocus: false,
+      revalidateOnReconnect: false
+    }
+  );
+
+  // v2改进：增量获取新消息
+  const { data: newMessages } = useSWR<RoomMessageListRes>(
+    selectedRoomId && lastMessageId > 0
+      ? `/api/room/message/getUpdate?roomId=${selectedRoomId}&sinceMessageId=${lastMessageId}`
+      : null,
     (key) => authFetch(key).then((r) => r.json().then((d: any) => d.data)),
     { refreshInterval: 1000 }
   );
 
+  // v2处理首次加载的消息
+  useEffect(() => {
+    if (initialMessages?.messages && isFirstLoad) {
+      setMessages(initialMessages.messages);
+      if (initialMessages.messages.length > 0) {
+        const lastMsg = initialMessages.messages[initialMessages.messages.length - 1];
+        setLastMessageId(lastMsg.messageId);
+      }
+      setIsFirstLoad(false);
+    }
+  }, [initialMessages, isFirstLoad]);
+
+  // v2处理增量更新的消息
+  useEffect(() => {
+    if (newMessages?.messages && newMessages.messages.length > 0) {
+      setMessages(prev => [...prev, ...newMessages.messages]);
+      const lastMsg = newMessages.messages[newMessages.messages.length - 1];
+      setLastMessageId(lastMsg.messageId);
+    }
+  }, [newMessages]);
+
+  // v2切换房间时重置状态
+  useEffect(() => {
+    setMessages([]);
+    setLastMessageId(0);
+    setIsFirstLoad(true);
+  }, [selectedRoomId]);
+
   // 创建房间
   const { trigger: addRoomTrigger, isMutating: isAddingRoom } = useSWRMutation<
     RoomAddRes,
@@ -240,15 +327,15 @@ export default function ChatPage() {
 
   // 删除房间
   const { trigger: deleteRoomTrigger } = useSWRMutation(
-  '/api/room/delete', // 确保路径正确
-  async (key, { arg }: { arg: { roomId: number } }) => {
-    const response = await authFetch(key, {
-      method: 'POST',
-      body: JSON.stringify({ roomId: arg.roomId }), // 参数格式修正
-    });
-    return response;
-  }
-);
+    '/api/room/delete',
+    async (key, { arg }: { arg: { roomId: number } }) => {
+      const response = await authFetch(key, {
+        method: 'POST',
+        body: JSON.stringify({ roomId: arg.roomId }),
+      });
+      return response;
+    }
+  );
 
   // 发送消息
   const { trigger: sendMessageTrigger, isMutating: isSendingMessage } =
@@ -279,7 +366,9 @@ export default function ChatPage() {
     try {
       const res = await addRoomTrigger({ user: nickname, roomName: newRoomName.trim() });
       refreshRooms();
-      if (res?.roomId) setSelectedRoomId(res.roomId);
+      if (res?.roomId) {
+        handleSelectRoom(res.roomId); // 🆕 使用新的设置函数
+      }
       setShowAddModal(false);
       setNewRoomName('');
     } catch (error) {
@@ -290,50 +379,46 @@ export default function ChatPage() {
 
   // 处理删除房间
   const handleDeleteRoom = async (roomId: number) => {
-  if (!isLoggedIn) {
-    alert('请先登录后再删除房间');
-    return;
-  }
-
-  const token = localStorage.getItem('token');
-  if (!token) {
-    alert('登录状态已过期，请重新登录');
-    logout();
-    return;
-  }
+    if (!isLoggedIn) {
+      alert('请先登录后再删除房间');
+      return;
+    }
 
-  if (!confirm('确定删除该房间？此操作不可撤销！')) return;
-  
-  try {
-    await deleteRoomTrigger({ roomId });
-    
-    // 删除成功后的处理
-    if (selectedRoomId === roomId) {
-      setSelectedRoomId(null);
+    const token = localStorage.getItem('token');
+    if (!token) {
+      alert('登录状态已过期，请重新登录');
+      logout();
+      return;
     }
+
+    if (!confirm('确定删除该房间？此操作不可撤销！')) return;
     
-    // 立即刷新房间列表
-    refreshRooms();
-    
-    alert('房间删除成功');
-  } catch (error) {
-    console.error('删除房间失败:', error);
-    
-    if (error instanceof Error) {
-      if (error.message.includes('认证') || error.message.includes('token')) {
-        alert('认证失败，请重新登录');
-        logout();
+    try {
+      await deleteRoomTrigger({ roomId });
+      
+      if (selectedRoomId === roomId) {
+        handleSelectRoom(null); // 🆕 使用新的设置函数
+      }
+      
+      refreshRooms();
+      alert('房间删除成功');
+    } catch (error) {
+      console.error('删除房间失败:', error);
+      
+      if (error instanceof Error) {
+        if (error.message.includes('认证') || error.message.includes('token')) {
+          alert('认证失败，请重新登录');
+          logout();
+        } else {
+          alert(`删除房间失败: ${error.message}`);
+        }
       } else {
-        alert(`删除房间失败: ${error.message}`);
+        alert('删除房间失败，请稍后重试');
       }
-    } else {
-      alert('删除房间失败，请稍后重试');
     }
-  }
-};
-
+  };
 
-  // 处理发送消息
+  //处理发送消息
   const handleSendMessage = async () => {
     if (!messageInput.trim() || !selectedRoomId) return;
     try {
@@ -343,7 +428,8 @@ export default function ChatPage() {
         sender: nickname,
       });
       setMessageInput('');
-      refreshMessages();
+      // 发送成功后，增量更新会自动获取新消息
+      // 不需要手动刷新
     } catch {
       alert('发送消息失败');
     }
@@ -360,6 +446,10 @@ export default function ChatPage() {
     return <div className={styles.loading}>正在检查登录状态...</div>;
   }
 
+  //计算加载和错误状态
+  const messageIsLoading = initialLoading && isFirstLoad;
+  const messageError = initialError;
+
   return (
     <main className={styles.chatContainer}>
       {/* 身份验证状态显示 */}
@@ -369,7 +459,7 @@ export default function ChatPage() {
         onLogout={logout}
       />
 
-      {/* 左侧房间列表 */}
+      {/* 左侧房间列表 - 修改点击事件 */}
       <div className={styles.sidebar}>
         <div className={styles.sidebarHeader}>
           <h2>聊天室</h2>
@@ -389,10 +479,10 @@ export default function ChatPage() {
             <RoomEntry
               key={r.roomId}
               room={r}
-              onClick={() => setSelectedRoomId(r.roomId)}
+              onClick={() => handleSelectRoom(r.roomId)} // 🆕 使用新的设置函数
               isActive={selectedRoomId === r.roomId}
               onDelete={() => handleDeleteRoom(r.roomId)}
-              canDelete={isLoggedIn} // 只有登录用户可以删除
+              canDelete={isLoggedIn}
             />
           ))}
         </div>
@@ -411,7 +501,7 @@ export default function ChatPage() {
             <div className={styles.messagesContainer}>
               {messageIsLoading && <div className={styles.loading}>加载消息中...</div>}
               {messageError && <div className={styles.error}>加载消息失败</div>}
-              {messageData?.messages?.map((m) => (
+              {messages.map((m) => (
                 <MessageItem key={m.messageId} message={m} currentUser={nickname} />
               ))}
             </div>
@@ -476,4 +566,4 @@ export default function ChatPage() {
       )}
     </main>
   );
-}
+}
\ No newline at end of file

chatroom/src/app/greet/greet.css

-div{
+/* chatroom/src/app/greet/greet.css */
+.div{
     color: #c3aae2;
     text-align: center;
     padding: 20px;