PHP $ _POST在MAMP服务器上为http：// localhost返回一个空数组

I am very new to the world of PHH and I am trying to implement some Rest API.

I have installed a MAMP server on my MAC. Then I wrote the following php code in api.php:

<?php
$api = new RestUtils;
$api->processRequest();

class RestUtils
{
public static function processRequest()
{
       $request_method = strtolower($_SERVER['REQUEST_METHOD']);
       var_dump($request_method);
       var_dump($_POST);
       var_dump($_REQUESTS);
    }
 }
?>

Then in my terminal window, I execute the following:

curl -X POST -H "Content-Type: application/json" -d '{"name": "john"}' http://localhost:8888/api.php

I get the following output:

string(4) "post"

array(0){ }

array(0){ }

When I call call

echo file_get_contents("php://input"); 

it returns {"name":"john"}

You're posting a raw string. If you're expecting to PHP to process that string into $_POST, you have to submit it as a key=value pair, e.g.

-d 'foo:{"name":"john"}'

and then

echo $_POST['foo'];