Automatically populating $HTTP_RAW_POST_DATA is deprecated and will be removed in a future version.

PHP 接口，使用 ajax post方式提交数据的时候报错： 

Automatically populating $HTTP_RAW_POST_DATA is deprecated and will be removed in a future version. To avoid this warning set 'always_populate_raw_post_data' to '-1' in php.ini and use the php://input stream instead.

解决方法：在php.ini中找到 always_populate_raw_post_data，而后把行的注释 ‘;’ 去掉。