我已经开发了一个Java代码，该代码使用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"}}'

我已经编写了此代码，但是它始终会给HTTP代码400错误的请求。我找不到丢失的内容。

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());  
}