diff --git a/code/rest/base_bean.go b/code/rest/base_bean.go
index 648f793..afe114f 100644
--- a/code/rest/base_bean.go
+++ b/code/rest/base_bean.go
@@ -33,10 +33,13 @@ func (this *BaseBean) PanicError(err error) {
 // find the current user from request.
 func (this *BaseBean) findUser(request *http.Request) *User {
 
-	//try to find from SessionCache.
-	sessionId := util.GetSessionUuidFromRequest(request, core.COOKIE_AUTH_KEY)
+	sessionId := request.FormValue("access_token") //支持私有文件预览，优先获取access_token
 	if sessionId == "" {
-		return nil
+		//try to find from SessionCache.
+		sessionId = util.GetSessionUuidFromRequest(request, core.COOKIE_AUTH_KEY)
+		if sessionId == "" {
+			return nil
+		}
 	}
 
 	cacheItem, err := core.CONTEXT.GetSessionCache().Value(sessionId)