ajax自己的php是可以取值的；<?php

//接收数据
$username = $_POST['username'];

//echo "用户名是".$username;
if($username=="yang"){
echo "用户名存在".$username;
}else{
echo "用户名可用".$username;
}
?>是可以的

可是放在tp框架里面就会提示
<br />
<b>Fatal error</b>
: Class 'Home\Controller\PublicController' not found in <b>D:\WWW\App\Home\Controller\IndexController.class.php</b>
on line <b>4</b><br />