解决yii2中 Class yii/web/JsonParser does not exist, ReflectionException问题

最近在调试RESTful API示例时，出现以下错误：

 {
     "name": "Exception",
     "message": "Class yii/web/JsonParser does not exist",
     "code": -1,
     "type": "ReflectionException",
     "file": "/Users/Desktop/workspaces/php/yii2-ims/vendor/yiisoft/yii2/di/Container.php",
     "line": 426,
     "stack-trace": [
         "#0 /Users/Desktop/workspaces/php/yii2-ims/vendor/yiisoft/yii2/di/Container.php(426): ReflectionClass->__construct('yii/web/JsonPar...')",
         "#1 /Users/Desktop/workspaces/php/yii2-ims/vendor/yiisoft/yii2/di/Container.php(364): yii\\di\\Container->getDependencies('yii/web/JsonPar...')",
         "#2 /Users/Desktop/workspaces/php/yii2-ims/vendor/yiisoft/yii2/di/Container.php(156): yii\\di\\Container->build('yii/web/JsonPar...', Array, Array)",
         "#3 /Users/Desktop/workspaces/php/yii2-ims/vendor/yiisoft/yii2/BaseYii.php(345): yii\\di\\Container->get('yii/web/JsonPar...', Array)",
         "#4 /Users/Desktop/workspaces/php/yii2-ims/vendor/yiisoft/yii2/web/Request.php(531): yii\\BaseYii::createObject('yii/web/JsonPar...')",
         "#5 /Users/Desktop/workspaces/php/yii2-ims/vendor/yiisoft/yii2/rest/CreateAction.php(51): yii\\web\\Request->getBodyParams()",
         "#6 [internal function]: yii\\rest\\CreateAction->run()",
         "#7 /Users/Desktop/workspaces/php/yii2-ims/vendor/yiisoft/yii2/base/Action.php(94): call_user_func_array(Array, Array)",
         "#8 /Users/Desktop/workspaces/php/yii2-ims/vendor/yiisoft/yii2/base/Controller.php(157): yii\\base\\Action->runWithParams(Array)",
         "#9 /Users/Desktop/workspaces/php/yii2-ims/vendor/yiisoft/yii2/base/Module.php(528): yii\\base\\Controller->runAction('create', Array)",
         "#10 /Users/Desktop/workspaces/php/yii2-ims/vendor/yiisoft/yii2/web/Application.php(103): yii\\base\\Module->runAction('deptinfo/create', Array)",
         "#11 /Users/Desktop/workspaces/php/yii2-ims/vendor/yiisoft/yii2/base/Application.php(386): yii\\web\\Application->handleRequest(Object(yii\\web\\Request))",
         "#12 /Users/Desktop/workspaces/php/yii2-ims/api/web/index.php(10): yii\\base\\Application->run()",
         "#13 {main}"
     ]
 }

其实，这是自己给自己挖的一个坑，结果把自己给陷进去了，下面是配置文件的代码：

'request' => [
            'class' => 'yii\web\Request',
            'parsers' => [
                'application/json' => 'yii/web/JsonParser',
            ],
        ],

问题就在于配置时将 “yii/web/JsonParser”写错了，正确的是 “yii\web\JsonParser”，命名空间应以反斜杠“\”分割，看似很小的问题，结果调试了很长时间才找到原因，所以在写代码配置的时候一定要认真仔细，以免被自己误导，浪费宝贵的时间。