$url = 'http://localhost/stream_api.php';

 $body = [

     'name'=>'lemon',

     'age'=>20,

     'sex'=>'gener'

 ];

 $opts = [

     'http'=>[

         'method'=>'POST', //这里区分大小写

         'content'=>json_encode($body),

         'header'=>'Content-type:application/x-www-form-urlencoded'

     ]

 ];

 //创建流上下文

 $context = stream_context_create($opts);

 //将上下文传入

 $res = file_get_contents($url,false,$context);

 print_r($res);

<?php

header('Content-type:application/json');

$body = @file_get_contents('php://input');

//file_put_contents('2.php',$body);

$data = json_decode($body,true);

$data['name'] = 'jack';

echo json_encode($data);