curl -X POST "https://api.dingtalk.io/topapi/user/getbyunionid" \
-H 'Content-Type:application/x-www-form-urlencoded;charset=utf-8' \
-d 'access_token=6348d21e-fb41-4745-a214-95bcf8c118f0' \
-d 'unionid=z21HjQliSzpw0YWCNxmii6u2Os62cZ62iSZ'

DingTalkClient client = new DefaultDingTalkClient("https://api.dingtalk.io/topapi/user/getbyunionid");
OapiUserGetbyunionidRequest req = new OapiUserGetbyunionidRequest();
req.setUnionid("z21HjQliSzpw0Yxxxxxx");
OapiUserGetbyunionidResponse rsp = client.execute(req, access_token);
System.out.println(rsp.getBody());

import dingtalk.api

req=dingtalk.api.OapiUserGetbyunionidRequest("https://api.dingtalk.io/topapi/user/getbyunionid")
req.unionid="z21HjQliSzpw0YWCNxmii6u2Os62cZ62iSZ"
try:
  resp= req.getResponse(access_token)
  print(resp)
except Exception,e:
  print(e)

include "TopSdk.php";
date_default_timezone_set('Asia/Shanghai');

$c = new DingTalkClient(DingTalkConstant::$CALL_TYPE_OAPI, DingTalkConstant::$METHOD_POST , DingTalkConstant::$FORMAT_JSON);
$req = new OapiUserGetbyunionidRequest;
$req->setUnionid("z21HjQliSzpw0YWCNxmii6u2Os62cZ62iSZ");
$resp = $c->execute($req, $access_token, "https://api.dingtalk.io/topapi/user/getbyunionid");

IDingTalkClient client = new DefaultDingTalkClient("https://api.dingtalk.io/topapi/user/getbyunionid");
OapiUserGetbyunionidRequest req = new OapiUserGetbyunionidRequest();
req.Unionid = "z21HjQliSzpw0YWCNxmii6u2Os62cZ62iSZ";
OapiUserGetbyunionidResponse rsp = client.Execute(req, access_token);
Console.WriteLine(rsp.Body);

{
  "errcode":"0",
  "errmsg":"ok",
  "result":{
   "contact_type":"0",
   "userid":"zhangsan"
  },
  "request_id": "zcqi5450rpit"
}