diff --git a/backend/src/app.ts b/backend/src/app.ts
index f3c6d5a..7f2fbc1 100644
--- a/backend/src/app.ts
+++ b/backend/src/app.ts
@@ -1,76 +1,146 @@
 // filepath: /d:/code/CloudDiskDown/backend/src/app.ts
 import "./types/express";
-import express from "express";
+import express, { Application } from "express";
 import cors from "cors";
 import cookieParser from "cookie-parser";
+import { QueryTypes } from "sequelize";
+
+// 路由和中间件导入
 import routes from "./routes/api";
 import { errorHandler } from "./middleware/errorHandler";
-import sequelize from "./config/database";
 import { authMiddleware } from "./middleware/auth";
+
+// 数据库和服务相关
+import sequelize from "./config/database";
 import GlobalSetting from "./models/GlobalSetting";
 import Searcher from "./services/Searcher";
 
-const app = express();
+// 常量配置
+const PUBLIC_ROUTES = ["/user/login", "/user/register"];
+const IMAGE_PATH = "tele-images";
+const DEFAULT_PORT = 8009;
 
-app.use(
-  cors({
-    origin: "*",
-    credentials: true,
-    methods: ["GET", "POST", "PUT", "DELETE", "OPTIONS"],
-    allowedHeaders: ["Content-Type", "Authorization", "Cookie"],
-  })
-);
-
-app.use(cookieParser());
-app.use(express.json());
-
-// 应用 token 验证中间件，排除登录和注册接口
-app.use((req, res, next) => {
-  if (
-    req.path === "/user/login" ||
-    req.path === "/user/register" ||
-    req.path.includes("tele-images")
-  ) {
-    return next();
-  }
-  authMiddleware(req, res, next);
-});
-
-app.use("/", routes);
-
-const initializeGlobalSettings = async (): Promise<void> => {
-  const settings = await GlobalSetting.findOne();
-  if (!settings) {
-    await GlobalSetting.create({
-      httpProxyHost: "127.0.0.1",
-      httpProxyPort: 7890,
-      isProxyEnabled: true,
-      CommonUserCode: 9527,
-      AdminUserCode: 230713,
-    });
-    console.log("Global settings initialized with default values.");
-  }
-  await Searcher.updateAxiosInstance();
+// 全局设置默认值
+const DEFAULT_GLOBAL_SETTINGS = {
+  httpProxyHost: "127.0.0.1",
+  httpProxyPort: 7890,
+  isProxyEnabled: false,
+  CommonUserCode: 9527,
+  AdminUserCode: 230713,
 };
 
-// 错误处理
-app.use(errorHandler);
+class App {
+  private app: Application;
 
-const PORT = process.env.PORT || 8009;
+  constructor() {
+    this.app = express();
+    this.setupMiddlewares();
+    this.setupRoutes();
+    this.setupErrorHandling();
+  }
 
-// 在同步前禁用外键约束，同步后重新启用
-sequelize
-  .query("PRAGMA foreign_keys = OFF") // 禁用外键
-  .then(() => sequelize.sync({ alter: true }))
-  .then(() => sequelize.query("PRAGMA foreign_keys = ON")) // 重新启用外键
-  .then(() => {
-    app.listen(PORT, async () => {
-      await initializeGlobalSettings();
-      console.log(`Server is running on port ${PORT}`);
+  private setupMiddlewares(): void {
+    // CORS 配置
+    this.app.use(
+      cors({
+        origin: "*",
+        credentials: true,
+        methods: ["GET", "POST", "PUT", "DELETE", "OPTIONS"],
+        allowedHeaders: ["Content-Type", "Authorization", "Cookie"],
+      })
+    );
+
+    this.app.use(cookieParser());
+    this.app.use(express.json());
+
+    // 身份验证中间件
+    this.app.use((req, res, next) => {
+      if (PUBLIC_ROUTES.includes(req.path) || req.path.includes(IMAGE_PATH)) {
+        return next();
+      }
+      authMiddleware(req, res, next);
     });
-  })
-  .catch((error) => {
-    console.error("Database sync failed:", error);
-  });
+  }
 
-export default app;
+  private setupRoutes(): void {
+    this.app.use("/", routes);
+  }
+
+  private setupErrorHandling(): void {
+    this.app.use(errorHandler);
+  }
+
+  private async initializeGlobalSettings(): Promise<void> {
+    try {
+      const settings = await GlobalSetting.findOne();
+      if (!settings) {
+        await GlobalSetting.create(DEFAULT_GLOBAL_SETTINGS);
+        console.log("✅ Global settings initialized with default values.");
+      }
+      await Searcher.updateAxiosInstance();
+    } catch (error) {
+      console.error("❌ Failed to initialize global settings:", error);
+      throw error;
+    }
+  }
+
+  private async cleanupBackupTables(): Promise<void> {
+    try {
+      // 查询所有以 '_backup' 结尾的备份表
+      const backupTables = await sequelize.query<{ name: string }>(
+        "SELECT name FROM sqlite_master WHERE type='table' AND name LIKE '%\\_backup%' ESCAPE '\\'",
+        { type: QueryTypes.SELECT }
+      );
+
+      // 逐个删除备份表
+      for (const table of backupTables) {
+        if (table?.name) {
+          await sequelize.query(`DROP TABLE IF EXISTS ${table.name}`);
+          console.log(`✅ Cleaned up backup table: ${table.name}`);
+        }
+      }
+    } catch (error) {
+      console.error("❌ Failed to cleanup backup tables:", error);
+      throw error;
+    }
+  }
+
+  public async start(): Promise<void> {
+    try {
+      // 数据库初始化流程
+      await sequelize.query("PRAGMA foreign_keys = OFF");
+      console.log("📝 Foreign keys disabled for initialization...");
+
+      await this.cleanupBackupTables();
+      console.log("🧹 Backup tables cleaned up");
+
+      await sequelize.sync({ alter: true });
+      console.log("📚 Database schema synchronized");
+
+      await sequelize.query("PRAGMA foreign_keys = ON");
+      console.log("🔐 Foreign keys re-enabled");
+
+      // 启动服务器
+      const port = process.env.PORT || DEFAULT_PORT;
+      this.app.listen(port, async () => {
+        await this.initializeGlobalSettings();
+        console.log(`
+🚀 Server is running on port ${port}
+🔧 Environment: ${process.env.NODE_ENV || "development"}
+        `);
+      });
+    } catch (error) {
+      console.error("❌ Failed to start server:", error);
+      process.exit(1);
+    }
+  }
+}
+
+// 创建并启动应用
+const application = new App();
+application.start().catch((error) => {
+  console.error("❌ Application failed to start:", error);
+  process.exit(1);
+});
+
+export default application;
diff --git a/backend/src/utils/axiosInstance.ts b/backend/src/utils/axiosInstance.ts
index 3626a26..09f7bba 100644
--- a/backend/src/utils/axiosInstance.ts
+++ b/backend/src/utils/axiosInstance.ts
@@ -13,7 +13,6 @@ export function createAxiosInstance(
   proxyConfig?: ProxyConfig
 ): AxiosInstance {
   let agent;
-  console.log(proxyConfig);
   if (useProxy && proxyConfig) {
     agent = tunnel.httpsOverHttp({
       proxy: proxyConfig,