restapi.php

<?php
$userData = array("username" => "admin", "password" => "java@123");
$ch = curl_init("http://127.0.0.1/magento2.2/index.php/rest/V1/integration/admin/token");
curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "POST");
curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($userData));
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, array("Content-Type: application/json", "Content-Lenght: " . strlen(json_encode($userData))));

$token = curl_exec($ch);

$ch = curl_init("http://127.0.0.1/magento2.2/index.php/rest/V1/customers/1");
curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "GET");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, array("Content-Type: application/json", "Authorization: Bearer " . json_decode($token)));

$result = curl_exec($ch);

echo $result;
// var_dump($result);
?>