diff --git a/library/think/Session.php b/library/think/Session.php
index 1e832779..217a33dc 100644
--- a/library/think/Session.php
+++ b/library/think/Session.php
@@ -1,244 +1,269 @@
-<?php
-// +----------------------------------------------------------------------
-// | ThinkPHP [ WE CAN DO IT JUST THINK ]
-// +----------------------------------------------------------------------
-// | Copyright (c) 2006~2016 http://thinkphp.cn All rights reserved.
-// +----------------------------------------------------------------------
-// | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )
-// +----------------------------------------------------------------------
-// | Author: liu21st <liu21st@gmail.com>
-// +----------------------------------------------------------------------
-
-namespace think;
-
-class Session
-{
-    protected static $prefix = '';
-
-    /**
-     * 设置或者获取session作用域（前缀）
-     * @param string $prefix
-     * @return string|void
-     */
-    public static function prefix($prefix = '')
-    {
-        if (empty($prefix)) {
-            return self::$prefix;
-        } else {
-            self::$prefix = $prefix;
-        }
-    }
-
-    /**
-     * session初始化
-     * @param array $config
-     * @return void
-     */
-    public static function init($config = [])
-    {
-        if (isset($config['prefix'])) {
-            self::$prefix = $config['prefix'];
-        }
-        if ($config['var_session_id'] && isset($_REQUEST[$config['var_session_id']])) {
-            session_id($_REQUEST[$config['var_session_id']]);
-        } elseif (isset($config['id']) && !empty($config['id'])) {
-            session_id($config['id']);
-        }
-        if (isset($config['name'])) {
-            session_name($config['name']);
-        }
-        if (isset($config['path'])) {
-            session_save_path($config['path']);
-        }
-        if (isset($config['domain'])) {
-            ini_set('session.cookie_domain', $config['domain']);
-        }
-        if (isset($config['expire'])) {
-            ini_set('session.gc_maxlifetime', $config['expire']);
-            ini_set('session.cookie_lifetime', $config['expire']);
-        }
-        if (isset($config['use_trans_sid'])) {
-            ini_set('session.use_trans_sid', $config['use_trans_sid'] ? 1 : 0);
-        }
-        if (isset($config['use_cookies'])) {
-            ini_set('session.use_cookies', $config['use_cookies'] ? 1 : 0);
-        }
-        if (isset($config['cache_limiter'])) {
-            session_cache_limiter($config['cache_limiter']);
-        }
-        if (isset($config['cache_expire'])) {
-            session_cache_expire($config['cache_expire']);
-        }
-        if (!empty($config['type'])) {
-            // 读取session驱动
-            $class = (!empty($config['namespace']) ? $config['namespace'] : '\\think\\session\\driver\\') . ucwords($config['type']);
-            // 检查驱动类
-            if (!session_set_save_handler(new $class())) {
-                throw new Exception('error session handler', 11700);
-            }
-        }
-        // 启动session
-        if (!empty($config['auto_start']) && PHP_SESSION_ACTIVE != session_status()) {
-            ini_set('session.auto_start', 0);
-            session_start();
-        }
-
-    }
-
-    /**
-     * session设置
-     * @param string $name session名称
-     * @param mixed $value session值
-     * @param string $prefix 作用域（前缀）
-     * @return void
-     */
-    public static function set($name, $value = '', $prefix = '')
-    {
-        $prefix = $prefix ? $prefix : self::$prefix;
-        if (strpos($name, '.')) {
-            // 二维数组赋值
-            list($name1, $name2) = explode('.', $name);
-            if ($prefix) {
-                $_SESSION[$prefix][$name1][$name2] = $value;
-            } else {
-                $_SESSION[$name1][$name2] = $value;
-            }
-        } elseif ($prefix) {
-            $_SESSION[$prefix][$name] = $value;
-        } else {
-            $_SESSION[$name] = $value;
-        }
-    }
-
-    /**
-     * session获取
-     * @param string $name session名称
-     * @param string $prefix 作用域（前缀）
-     * @return mixed
-     */
-    public static function get($name = '', $prefix = '')
-    {
-        $prefix = $prefix ? $prefix : self::$prefix;
-        if ('' == $name) {
-            // 获取全部的session
-            $value = $prefix ? $_SESSION[$prefix] : $_SESSION;
-        } elseif ($prefix) {
-            // 获取session
-            if (strpos($name, '.')) {
-                list($name1, $name2) = explode('.', $name);
-                $value               = isset($_SESSION[$prefix][$name1][$name2]) ? $_SESSION[$prefix][$name1][$name2] : null;
-            } else {
-                $value = isset($_SESSION[$prefix][$name]) ? $_SESSION[$prefix][$name] : null;
-            }
-        } else {
-            if (strpos($name, '.')) {
-                list($name1, $name2) = explode('.', $name);
-                $value               = isset($_SESSION[$name1][$name2]) ? $_SESSION[$name1][$name2] : null;
-            } else {
-                $value = isset($_SESSION[$name]) ? $_SESSION[$name] : null;
-            }
-        }
-        return $value;
-    }
-
-    /**
-     * 删除session数据
-     * @param string $name session名称
-     * @param string $prefix 作用域（前缀）
-     * @return void
-     */
-    public static function delete($name, $prefix = '')
-    {
-        $prefix = $prefix ? $prefix : self::$prefix;
-        if (strpos($name, '.')) {
-            list($name1, $name2) = explode('.', $name);
-            if ($prefix) {
-                unset($_SESSION[$prefix][$name1][$name2]);
-            } else {
-                unset($_SESSION[$name1][$name2]);
-            }
-        } else {
-            if ($prefix) {
-                unset($_SESSION[$prefix][$name]);
-            } else {
-                unset($_SESSION[$name]);
-            }
-        }
-    }
-
-    /**
-     * 清空session数据
-     * @param string $prefix 作用域（前缀）
-     * @return void
-     */
-    public static function clear($prefix = '')
-    {
-        $prefix = $prefix ? $prefix : self::$prefix;
-        if ($prefix) {
-            unset($_SESSION[$prefix]);
-        } else {
-            $_SESSION = [];
-        }
-    }
-
-    /**
-     * 判断session数据
-     *
-     * @param string $name session名称
-     * @param string $prefix
-     *
-     * @return bool
-     * @internal param mixed $value session值
-     */
-    public static function has($name, $prefix = '')
-    {
-        $prefix = $prefix ? $prefix : self::$prefix;
-        if (strpos($name, '.')) {
-            // 支持数组
-            list($name1, $name2) = explode('.', $name);
-            return $prefix ? isset($_SESSION[$prefix][$name1][$name2]) : isset($_SESSION[$name1][$name2]);
-        } else {
-            return $prefix ? isset($_SESSION[$prefix][$name]) : isset($_SESSION[$name]);
-        }
-    }
-
-    /**
-     * 暂停session
-     * @return void
-     */
-    public static function pause()
-    {
-        // 暂停session
-        session_write_close();
-    }
-
-    /**
-     * 启动session
-     * @return void
-     */
-    public static function start()
-    {
-        session_start();
-    }
-
-    /**
-     * 销毁session
-     * @return void
-     */
-    public static function destroy()
-    {
-        $_SESSION = [];
-        session_unset();
-        session_destroy();
-    }
-
-    /**
-     * 重新生成session_id
-     * @return void
-     */
-    private static function regenerate()
-    {
-        session_regenerate_id();
-    }
-
-}
+<?php
+// +----------------------------------------------------------------------
+// | ThinkPHP [ WE CAN DO IT JUST THINK ]
+// +----------------------------------------------------------------------
+// | Copyright (c) 2006~2016 http://thinkphp.cn All rights reserved.
+// +----------------------------------------------------------------------
+// | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )
+// +----------------------------------------------------------------------
+// | Author: liu21st <liu21st@gmail.com>
+// +----------------------------------------------------------------------
+namespace think;
+
+class Session
+{
+
+    protected static $prefix = '';
+
+    /**
+     * 设置或者获取session作用域（前缀）
+     *
+     * @param string $prefix            
+     * @return string|void
+     */
+    public static function prefix($prefix = '')
+    {
+        if (empty($prefix) && $prefix !== null) {
+            return self::$prefix;
+        } else {
+            self::$prefix = $prefix;
+        }
+    }
+
+    /**
+     * session初始化
+     *
+     * @param array $config            
+     * @return void
+     */
+    public static function init($config = [])
+    {
+        $isDoStart = false;
+        if (isset($config['use_trans_sid'])) {
+            ini_set('session.use_trans_sid', $config['use_trans_sid'] ? 1 : 0);
+        }
+        
+        // 启动session
+        if (! empty($config['auto_start']) && PHP_SESSION_ACTIVE != session_status()) {
+            ini_set('session.auto_start', 0);
+            $isDoStart = true;
+        }
+        
+        if (isset($config['prefix'])) {
+            self::$prefix = $config['prefix'];
+        }
+        if ($config['var_session_id'] && isset($_REQUEST[$config['var_session_id']])) {
+            session_id($_REQUEST[$config['var_session_id']]);
+        } elseif (isset($config['id']) && ! empty($config['id'])) {
+            session_id($config['id']);
+        }
+        if (isset($config['name'])) {
+            session_name($config['name']);
+        }
+        if (isset($config['path'])) {
+            session_save_path($config['path']);
+        }
+        if (isset($config['domain'])) {
+            ini_set('session.cookie_domain', $config['domain']);
+        }
+        if (isset($config['expire'])) {
+            ini_set('session.gc_maxlifetime', $config['expire']);
+            ini_set('session.cookie_lifetime', $config['expire']);
+        }
+        
+        if (isset($config['use_cookies'])) {
+            ini_set('session.use_cookies', $config['use_cookies'] ? 1 : 0);
+        }
+        if (isset($config['cache_limiter'])) {
+            session_cache_limiter($config['cache_limiter']);
+        }
+        if (isset($config['cache_expire'])) {
+            session_cache_expire($config['cache_expire']);
+        }
+        if (! empty($config['type'])) {
+            // 读取session驱动
+            $class = (! empty($config['namespace']) ? $config['namespace'] : '\\think\\session\\driver\\') . ucwords($config['type']);
+            
+            // 检查驱动类
+            if (! class_exists($class) || ! session_set_save_handler(new $class())) {
+                throw new \think\Exception('error session handler', 11700);
+            }
+        }
+        if ($isDoStart) {
+            session_start();
+        }
+    }
+
+    /**
+     * session设置
+     *
+     * @param string $name
+     *            session名称
+     * @param mixed $value
+     *            session值
+     * @param string $prefix
+     *            作用域（前缀）
+     * @return void
+     */
+    public static function set($name, $value = '', $prefix = '')
+    {
+        $prefix = $prefix ? $prefix : self::$prefix;
+        if (strpos($name, '.')) {
+            // 二维数组赋值
+            list ($name1, $name2) = explode('.', $name);
+            if ($prefix) {
+                $_SESSION[$prefix][$name1][$name2] = $value;
+            } else {
+                $_SESSION[$name1][$name2] = $value;
+            }
+        } elseif ($prefix) {
+            $_SESSION[$prefix][$name] = $value;
+        } else {
+            $_SESSION[$name] = $value;
+        }
+    }
+
+    /**
+     * session获取
+     *
+     * @param string $name
+     *            session名称
+     * @param string $prefix
+     *            作用域（前缀）
+     * @return mixed
+     */
+    public static function get($name = '', $prefix = '')
+    {
+        $prefix = $prefix ? $prefix : self::$prefix;
+        if ('' == $name) {
+            // 获取全部的session
+            $value = $prefix ? $_SESSION[$prefix] : $_SESSION;
+        } elseif ($prefix) {
+            // 获取session
+            if (strpos($name, '.')) {
+                list ($name1, $name2) = explode('.', $name);
+                $value = isset($_SESSION[$prefix][$name1][$name2]) ? $_SESSION[$prefix][$name1][$name2] : null;
+            } else {
+                $value = isset($_SESSION[$prefix][$name]) ? $_SESSION[$prefix][$name] : null;
+            }
+        } else {
+            if (strpos($name, '.')) {
+                list ($name1, $name2) = explode('.', $name);
+                $value = isset($_SESSION[$name1][$name2]) ? $_SESSION[$name1][$name2] : null;
+            } else {
+                $value = isset($_SESSION[$name]) ? $_SESSION[$name] : null;
+            }
+        }
+        return $value;
+    }
+
+    /**
+     * 删除session数据
+     *
+     * @param string $name
+     *            session名称
+     * @param string $prefix
+     *            作用域（前缀）
+     * @return void
+     */
+    public static function delete($name, $prefix = '')
+    {
+        $prefix = $prefix ? $prefix : self::$prefix;
+        if (strpos($name, '.')) {
+            list ($name1, $name2) = explode('.', $name);
+            if ($prefix) {
+                unset($_SESSION[$prefix][$name1][$name2]);
+            } else {
+                unset($_SESSION[$name1][$name2]);
+            }
+        } else {
+            if ($prefix) {
+                unset($_SESSION[$prefix][$name]);
+            } else {
+                unset($_SESSION[$name]);
+            }
+        }
+    }
+
+    /**
+     * 清空session数据
+     *
+     * @param string $prefix
+     *            作用域（前缀）
+     * @return void
+     */
+    public static function clear($prefix = '')
+    {
+        $prefix = $prefix ? $prefix : self::$prefix;
+        if ($prefix) {
+            unset($_SESSION[$prefix]);
+        } else {
+            $_SESSION = [];
+        }
+    }
+
+    /**
+     * 判断session数据
+     *
+     * @param string $name
+     *            session名称
+     * @param string $prefix            
+     *
+     * @return bool
+     * @internal param mixed $value session值
+     */
+    public static function has($name, $prefix = '')
+    {
+        $prefix = $prefix ? $prefix : self::$prefix;
+        if (strpos($name, '.')) {
+            // 支持数组
+            list ($name1, $name2) = explode('.', $name);
+            return $prefix ? isset($_SESSION[$prefix][$name1][$name2]) : isset($_SESSION[$name1][$name2]);
+        } else {
+            return $prefix ? isset($_SESSION[$prefix][$name]) : isset($_SESSION[$name]);
+        }
+    }
+
+    /**
+     * 暂停session
+     *
+     * @return void
+     */
+    public static function pause()
+    {
+        // 暂停session
+        session_write_close();
+    }
+
+    /**
+     * 启动session
+     *
+     * @return void
+     */
+    public static function start()
+    {
+        session_start();
+    }
+
+    /**
+     * 销毁session
+     *
+     * @return void
+     */
+    public static function destroy()
+    {
+        $_SESSION = [];
+        session_unset();
+        session_destroy();
+    }
+
+    /**
+     * 重新生成session_id
+     *
+     * @return void
+     */
+    private static function regenerate()
+    {
+        session_regenerate_id();
+    }
+}