java curl json_POST请求发送json数据java HttpUrlConnection

我开发了一个java代码，使用URL和HttpUrlConnection将以下cURL转换为java代码。卷曲是：

curl -i 'http://url.com' -X POST -H "Content-Type: application/json" -H "Accept: application/json" -d '{"auth": { "passwordCredentials": {"username": "adm", "password": "pwd"},"tenantName":"adm"}}'

我编写了这段代码，但它始终给出了HTTP代码400错误的请求。我找不到遗漏的东西。

String url="http://url.com";

URL object=new URL(url);

HttpURLConnection con = (HttpURLConnection) object.openConnection();

con.setDoOutput(true);

con.setDoInput(true);

con.setRequestProperty("Content-Type", "application/json");

con.setRequestProperty("Accept", "application/json");

con.setRequestMethod("POST");

JSONObject cred   = new JSONObject();

JSONObject auth   = new JSONObject();

JSONObject parent = new JSONObject();

cred.put("username","adm");

cred.put("password", "pwd");

auth.put("tenantName", "adm");

auth.put("passwordCredentials", cred.toString());

parent.put("auth", auth.toString());

OutputStreamWriter wr = new OutputStreamWriter(con.getOutputStream());

wr.write(parent.toString());

wr.flush();

//display what returns the POST request

StringBuilder sb = new StringBuilder();

int HttpResult = con.getResponseCode();

if (HttpResult == HttpURLConnection.HTTP_OK) {

BufferedReader br = new BufferedReader(

new InputStreamReader(con.getInputStream(), "utf-8"));

String line = null;

while ((line = br.readLine()) != null) {

sb.append(line + "n");

}

br.close();

System.out.println("" + sb.toString());

} else {

System.out.println(con.getResponseMessage());

}