添加初始化页面

server/db.js

@@ -1,14 +1,26 @@
 const mysql = require('mysql2/promise');
 
-const pool = mysql.createPool({
-  host: process.env.MYSQL_HOST || 'localhost',
-  port: parseInt(process.env.MYSQL_PORT) || 3306,
-  user: process.env.MYSQL_USER || 'root',
-  password: process.env.MYSQL_PASSWORD || '',
-  database: process.env.MYSQL_DATABASE || 'display_wall',
-  waitForConnections: true,
-  connectionLimit: 10,
-  queueLimit: 0
-});
+let pool;
 
-module.exports = pool;
+function initPool() {
+  if (pool) {
+    pool.end().catch(e => console.error('Error closing pool:', e));
+  }
+  pool = mysql.createPool({
+    host: process.env.MYSQL_HOST || 'localhost',
+    port: parseInt(process.env.MYSQL_PORT) || 3306,
+    user: process.env.MYSQL_USER || 'root',
+    password: process.env.MYSQL_PASSWORD || '',
+    database: process.env.MYSQL_DATABASE || 'display_wall',
+    waitForConnections: true,
+    connectionLimit: 10,
+    queueLimit: 0
+  });
+}
+
+initPool();
+
+module.exports = {
+  query: (...args) => pool.query(...args),
+  initPool
+};