diff --git a/library/think/cache/driver/Memcached.php b/library/think/cache/driver/Memcached.php
index 93e58267..50082a1e 100644
--- a/library/think/cache/driver/Memcached.php
+++ b/library/think/cache/driver/Memcached.php
@@ -12,19 +12,18 @@
 namespace think\cache\driver;
 
 use think\Cache;
-use think\Exception;
 
 class Memcached
 {
-    protected $handler = null;
+    protected $handler;
     protected $options = [
-        'host'    => '127.0.0.1',
-        'port'    => 11211,
-        'expire'  => 0,
-        'timeout' => 0, // 超时时间（单位：毫秒）
-        'prefix'  => '',
-        'username'     => '', //账号
-        'password'     => '', //密码
+        'host'     => '127.0.0.1',
+        'port'     => 11211,
+        'expire'   => 0,
+        'timeout'  => 0, // 超时时间（单位：毫秒）
+        'prefix'   => '',
+        'username' => '', //账号
+        'password' => '', //密码
     ];
 
     /**
@@ -57,9 +56,9 @@ class Memcached
             $servers[] = [$host, (isset($ports[$i]) ? $ports[$i] : $ports[0]), 1];
         }
         $this->handler->addServers($servers);
-        if('' != $this->options['username']){
+        if ('' != $this->options['username']) {
             $this->handler->setOption(\Memcached::OPT_BINARY_PROTOCOL, true);
-            $this->handler->setSaslAuthData($this->options['username'], $this->options['password']);  
+            $this->handler->setSaslAuthData($this->options['username'], $this->options['password']);
         }
     }
 
diff --git a/library/think/cache/driver/Sqlite.php b/library/think/cache/driver/Sqlite.php
index 8a7c19aa..e4689d61 100644
--- a/library/think/cache/driver/Sqlite.php
+++ b/library/think/cache/driver/Sqlite.php
@@ -18,7 +18,7 @@ use think\Exception;
  * Sqlite缓存驱动
  * @author    liu21st <liu21st@gmail.com>
  */
-class Sqlite implements CacheInterface
+class Sqlite
 {
 
     protected $options = [