微信公众号获取acess_token并存储（php）

<?php
define("appid", "你的appid");
define("appsecret", "你的appsecret");

//获取access_token，每7000s重新获取
function getAccessToken() {
$tokenFile = "./access_token.txt";
$data = json_decode(file_get_contents($tokenFile));

if ($data->expire_time < time() || !$data->expire_time) {
$appid = appid;
$appsecret = appsecret;
$url = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=$appid&secret=$appsecret";
$res = json_decode(file_get_contents($url));
$access_token = $res->access_token;
if($access_token) {
$data_new['expire_time'] = time() + 7000;
$data_new['access_token'] = $access_token;
file_put_contents($tokenFile, json_encode($data_new));
}
}else{
$access_token = $data->access_token;
}
return $access_token;
}

// var_dump(getAccessToken());
?>