diff --git a/src/Api.php b/src/Api.php
index 8e9850a..61b4e0a 100644
--- a/src/Api.php
+++ b/src/Api.php
@@ -208,10 +208,11 @@ protected function userCheck() {
      * @return boolean
      */
     protected function isServiceWhitelist() {
-        $api = DI()->request->getServiceApi();
-        $action = DI()->request->getServiceAction();
+        $di = DI();
+        $api = $di->request->getServiceApi();
+        $action = $di->request->getServiceAction();
 
-        $serviceWhitelist = DI()->config->get('app.service_whitelist', array());
+        $serviceWhitelist = $di->config->get('app.service_whitelist', array());
         foreach ($serviceWhitelist as $item) {
             $cfgArr = explode('.', $item);
             if (count($cfgArr) < 2) {
diff --git a/src/ApiFactory.php b/src/ApiFactory.php
index 9fa6aad..b81e916 100644
--- a/src/ApiFactory.php
+++ b/src/ApiFactory.php
@@ -39,10 +39,11 @@ class ApiFactory {
      * @throws BadRequestException 非法请求下返回400
      */
     static function generateService($isInitialize = TRUE) {
-        $service    = DI()->request->getService();
-        $namespace  = DI()->request->getNamespace();
-        $api        = DI()->request->getServiceApi();
-        $action     = DI()->request->getServiceAction();
+        $di         = DI();
+        $service    = $di->request->getService();
+        $namespace  = $di->request->getNamespace();
+        $api        = $di->request->getServiceApi();
+        $action     = $di->request->getServiceAction();
 
         if (empty($api) || empty($action)) {
             throw new BadRequestException(
diff --git a/src/DependenceInjection.php b/src/DependenceInjection.php
index 8ba8273..68e69e5 100644
--- a/src/DependenceInjection.php
+++ b/src/DependenceInjection.php
@@ -113,7 +113,7 @@ public function onInitialize() {
      * @parms mixed $value service的值，可以是具体的值或实例、类名、匿名函数、数组配置
      */ 
     public function set($key, $value) {
-        $this->resetHit($key);
+        $this->hitTimes[$key] = 0;
 
         $this->data[$key] = $value;
 
@@ -137,9 +137,13 @@ public function get($key, $default = NULL) {
             $this->data[$key] = $default;
         }
 
-        $this->recordHitTimes($key);
+        // 内联操作，减少函数调用，提升性能
+        if (!isset($this->hitTimes[$key])) {
+            $this->hitTimes[$key] = 0;
+        }
+        $this->hitTimes[$key] ++;
 
-        if ($this->isFirstHit($key)) {
+        if ($this->hitTimes[$key] == 1) {
             $this->data[$key] = $this->initService($this->data[$key]);
         }
 
@@ -206,21 +210,5 @@ protected function initService($config) {
 
         return $rs;
     }
-
-    protected function resetHit($key) {
-        $this->hitTimes[$key] = 0;
-    }
-
-    protected function isFirstHit($key) {
-        return $this->hitTimes[$key] == 1;
-    }
-
-    protected function recordHitTimes($key) {
-        if (!isset($this->hitTimes[$key])) {
-            $this->hitTimes[$key] = 0;
-        }
-
-        $this->hitTimes[$key] ++;
-    }
 }
 
diff --git a/src/PhalApi.php b/src/PhalApi.php
index 679559e..0853c61 100644
--- a/src/PhalApi.php
+++ b/src/PhalApi.php
@@ -40,11 +40,12 @@ class PhalApi {
 ```
      */
     public function response() {
-        $rs = DI()->response;
+        $di = DI();
+        $rs = $di->response;
         try {
             // 接口调度与响应
             $api    = ApiFactory::generateService(); 
-            $action = DI()->request->getServiceAction();
+            $action = $di->request->getServiceAction();
             $data   = call_user_func(array($api, $action));
 
             $rs->setData($data);
@@ -54,9 +55,9 @@ public function response() {
             $rs->setMsg($ex->getMessage());
         } catch (\Exception $ex) {
             // 不可控的异常
-            DI()->logger->error(DI()->request->getService(), strval($ex));
+            $di->logger->error(DI()->request->getService(), strval($ex));
 
-            if (DI()->debug) {
+            if ($di->debug) {
                 $rs->setRet($ex->getCode());
                 $rs->setMsg($ex->getMessage());
                 $rs->setDebug('exception', $ex->getTrace());
@@ -65,8 +66,8 @@ public function response() {
             }
         }
 
-        $rs->setDebug('stack', DI()->tracer->getStack());
-        $rs->setDebug('sqls', DI()->tracer->getSqls());
+        $rs->setDebug('stack', $di->tracer->getStack());
+        $rs->setDebug('sqls', $di->tracer->getSqls());
         $rs->setDebug('version', PHALAPI_VERSION);
 
         return $rs;
diff --git a/src/Request.php b/src/Request.php
index 4955b12..08593c4 100644
--- a/src/Request.php
+++ b/src/Request.php
@@ -44,7 +44,7 @@ class Request {
     /**
      * @var array $headers 备用数据源 请求头部信息
      */
-    protected $headers = array();
+    protected $headers;
 
     /**
      * @var string 接口服务命名空间
@@ -91,7 +91,6 @@ public function __construct($data = NULL) {
         $this->data     = $this->genData($data);
 
         // 备用数据源
-        $this->headers  = $this->getAllHeaders();
         $this->get      = $_GET;
         $this->post     = $_POST;
         $this->request  = $_REQUEST;
@@ -150,6 +149,11 @@ protected function getAllHeaders() {
      * @return string
      */
     public function getHeader($key, $default = NULL) {
+        // 延时加载，提升性能
+        if ($this->headers === NULL) {
+            $this->headers = $this->getAllHeaders();
+        }
+
         return isset($this->headers[$key]) ? $this->headers[$key] : $default;
     }
 
@@ -223,6 +227,9 @@ protected function &getDataBySource($source) {
         case 'COOKIE':
             return $this->cookie;
         case 'HEADER':
+            if ($this->headers === NULL) {
+                $this->headers = $this->getAllHeaders();
+            }
             return $this->headers;
         case 'SERVER':
             return $_SERVER;