模拟提交http_post_data发送数据的获取方式

function http_post_data($url, $data_string) {
	$ch = curl_init();
	curl_setopt($ch, CURLOPT_POST, 1);
	curl_setopt($ch, CURLOPT_URL, $url);
	curl_setopt($ch, CURLOPT_POSTFIELDS, $data_string);
	curl_setopt($ch, CURLOPT_HTTPHEADER, array(
		'Content-Type: application/json; charset=utf-8',
		'Content-Length: ' . strlen($data_string))
	);
	ob_start();
	$ret = curl_exec($ch);
	if (curl_errno($ch)) {
		// $this->ErrorLogger('curl post falied. Error Info: '.curl_error($ch));
	}
	$return_content = ob_get_contents();
	ob_end_clean();
	return $return_content;
}

$data = array('username' => 'nihao', 'password' => 'nihao') );
$rs = http_post_data($url, json_encode($data));

$data = json_decode($GLOBALS['HTTP_RAW_POST_DATA'], true);

$postdata = file_get_contents("php://input"); //json
$data = json_decode($postdata, true);