feature: 数据库连接与SQL集中管理，提高代码可读性

db/connection.py

@@ -0,0 +1,51 @@
+# -*- coding: utf-8 -*-
+import logging
+import mysql.connector.pooling
+import redis
+from typing import Optional
+
+
+class DBConnectionManager:
+    """数据库连接管理类，用于管理MySQL和Redis连接池"""
+    
+    _instance = None
+    
+    def __new__(cls, *args, **kwargs):
+        if cls._instance is None:
+            cls._instance = super(DBConnectionManager, cls).__new__(cls)
+            cls._instance.initialized = False
+        return cls._instance
+    
+    def __init__(self, mysql_config: Optional[dict] = None, redis_config: Optional[dict] = None):
+        if self.initialized:
+            return
+            
+        self.LOG = logging.getLogger("DBConnectionManager")
+        
+        # 初始化MySQL连接池
+        if mysql_config:
+            self.mysql_pool = mysql.connector.pooling.MySQLConnectionPool(**mysql_config)
+            self.LOG.info(f"MySQL连接池初始化完成: {mysql_config}")
+        else:
+            self.mysql_pool = None
+            
+        # 初始化Redis连接池
+        if redis_config:
+            self.redis_pool = redis.ConnectionPool(**redis_config)
+            self.LOG.info(f"Redis连接池初始化完成: {redis_config}")
+        else:
+            self.redis_pool = None
+            
+        self.initialized = True
+    
+    def get_mysql_connection(self):
+        """获取MySQL连接"""
+        if not self.mysql_pool:
+            raise Exception("MySQL连接池未初始化")
+        return self.mysql_pool.get_connection()
+    
+    def get_redis_connection(self):
+        """获取Redis连接"""
+        if not self.redis_pool:
+            raise Exception("Redis连接池未初始化")
+        return redis.Redis(connection_pool=self.redis_pool)