Android REST API發布

Question

我正在嘗試第一次從Android調用rest api。 我正在使用post方法。這是我的代碼。 我的HTTP狀態碼為500。我在做什么錯。

public void loginUser(View view) {
    EditText user = (EditText) findViewById(R.id.enter_username);
    EditText pass = (EditText) findViewById(R.id.enter_password);
    String username = user.getText().toString();
    String password = pass.getText().toString();
    if (username != null && !username.isEmpty() && password != null && !password.isEmpty()) {
        String urlString = "URL TO BE ENTERED HERE"; //TO DO
        //new CallAPI().execute(urlString);
        new PostLoginData().execute(urlString);
    }

}

private class PostLoginData extends AsyncTask<String, String, String> {

    @Override
    protected String doInBackground(String... params){
        EditText user = (EditText) findViewById(R.id.enter_username);
        EditText pass = (EditText) findViewById(R.id.enter_password);
        String username = user.getText().toString();
        String password = pass.getText().toString();
        String message = null;

        HttpClient httpClient = new DefaultHttpClient();
        HttpPost httpPost = new HttpPost("http://test.gogch.com/gch-restful/login");
        List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
        nameValuePairs.add(new BasicNameValuePair("username",username));
        nameValuePairs.add(new BasicNameValuePair("password",password));
        try {
            httpPost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
        }
        catch (UnsupportedEncodingException e){
            e.printStackTrace();
        }
        try {
            HttpResponse response = httpClient.execute(httpPost);
            int statusCode = response.getStatusLine().getStatusCode();
            Log.d("Http Post Response:" ,Integer.toString(statusCode));
            message = response.toString();
        }
        catch(ClientProtocolException e){
            e.printStackTrace();
        }
        catch (IOException e){
            e.printStackTrace();
        }
        return message;
    }

    protected void onPostExecute(String result){
        Intent intent = new Intent(getApplicationContext(), DisplayMessageActivity.class);
        intent.putExtra(EXTRA_MESSAGE, result);
        startActivity(intent);
    }
}

json

{
message: "The email or password you entered is incorrect."
isExpired: false
status: false
}

我實際上正在嘗試的是從json中提取狀態。 請告訴我如何正確獲取回復文本。