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Java REST API: POST Method gets NULL parameters

I'm sending parameters from my android app to the backend and trying to retrieve the parameters sent by my android clients in my POST Method but I keep getting null parameters even though the clients are sending parameters which are not null.
Java POST Method:
#POST
#Produces({ "application/json" })
#Path("/login")
public LoginResponse Login(#FormParam("email") String email, #FormParam("password") String password) {
LoginResponse response = new LoginResponse();
if(email != null && password != null && email.length() != 0 && password.length() != 0){
//Detect if null or empty
//Code
}
return response;
}
Android Client:
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://MY_APP_NAME.appspot.com/user/login");
String json = "";
JSONObject jsonObject = new JSONObject();
try {
jsonObject.accumulate("email", "roger#gmail.com");
jsonObject.accumulate("password", "123");
json = jsonObject.toString();
StringEntity se = new StringEntity(json);
httppost.setEntity(se);
httppost.setHeader("Content-Type", "application/json");
httppost.setHeader("ACCEPT", "application/json");
HttpResponse httpResponse = httpclient.execute(httppost);
}
catch(Exception ex) { }
I believe the Content-Type of the method and the client is the same as well. Why am I not receiving the parameters from the Java Backend Method?
CHECKED:
The URL is correct and the connection is working
The Parameters sent by the app are not null

We hope i got you, try NameValuePair
public void postData() {
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://www.yoursite.com/yourscript.php");
try {
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
nameValuePairs.add(new BasicNameValuePair("id", "123"));
nameValuePairs.add(new BasicNameValuePair("string", "Hey"));
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
// Execute HTTP Post Request
HttpResponse response = httpclient.execute(httppost);
} catch (ClientProtocolException e) {
// Catch Protocol Exception
} catch (IOException e) {
// Catch IOException
}
}

Just in case you have similar problems, I'd suggest using Fiddler
which is a free http inspector and debugger by which you can see the http request your app is sending to the backend server and the backend answer.
Best of luck

Oauth token requests before provider credentials issuance

Please forgive me if I ask something stupid, I am a novice here. I need to implement OAuth in my Java application to authenticate against launchpad.net API. The documentation specifies an initiation of a token request with three parameters : oauth_consumer_key e.g. (name of my application), oauth_signature_method e.g. "PLAINTEXT" and oauth_signature e.g. The string "&". I realised that most OAuth libraries require that
I have already acquired a Consumer key and Consumer Id/Secret from
the OAuth provider (e.g as issued in Twitter), and most examples are organised in this manner. However, launchpad.net will issue these parameters only after issuance of request token (they use no third party provider). How can I proceed?I am currently stuck after trying some libraries that threw errors. Many thanks for any useful information. The official launchpad library is in python.
My initial code is below:
public class Quicky {
public static void main(String[] args) throws Exception {
CloseableHttpClient httpclient = HttpClients.createDefault();
try {
HttpGet httpGet = new HttpGet("https://launchpad.net/+request-token");
CloseableHttpResponse response1 = httpclient.execute(httpGet);
try {
System.out.println("Your current GET request status:" + response1.getStatusLine());
HttpEntity entity1 = response1.getEntity();
EntityUtils.consume(entity1);
} finally {
response1.close();
}
HttpRequest request;
HttpPost httpPost = new HttpPost("https://launchpad.net/+request-token");
PostMethod poster = new PostMethod();
List <NameValuePair> postParams = new ArrayList <NameValuePair>();
postParams.add(new BasicNameValuePair("oauth_customer_key", "XXXX"));
postParams.add(new BasicNameValuePair("oauth_signature_method", "PLAINTEXT"));
postParams.add(new BasicNameValuePair("oauth_signature", "&"));
httpPost.setEntity(new UrlEncodedFormEntity(postParams, "utf-8"));
// httpPost.setEntity(entity1);
httpclient.execute(httpPost);
HttpParameters requestParams = (HttpParameters) postParams;
CloseableHttpResponse response2 = httpclient.execute(httpPost);
try {
System.out.println("Your current POST request status:" + response2.getStatusLine());
HttpEntity entity2 = response2.getEntity();
// do something useful with the response body
// and ensure it is fully consumed
EntityUtils.consume(entity2);
} finally {
response2.close();
}
} finally {
httpclient.close();
}
}
}

I finally resolved the issue error messages after some research and code re-factoring. The correct code is below, maybe it could be useful to someone out there.
public class LaunchPadTokenRetriever {
public static void main(String[] args) throws ClientProtocolException, IOException{
CloseableHttpClient httpclient = HttpClients.createDefault();
HttpPost httpPost = new HttpPost("https://launchpad.net/+request-token");
httpPost.addHeader("Content-Type", "application/x-www-form-urlencoded");
List <NameValuePair> urlParams = new ArrayList <NameValuePair>();
urlParams.add(new BasicNameValuePair("oauth_signature", "&"));
urlParams.add(new BasicNameValuePair("oauth_consumer_key", "tester"));
urlParams.add(new BasicNameValuePair("oauth_signature_method", "PLAINTEXT"));
httpPost.setEntity(new UrlEncodedFormEntity(urlParams));
CloseableHttpResponse response = httpclient.execute(httpPost);
System.out.println(response);
try {
System.out.println(response.getStatusLine());
HttpEntity entity = response.getEntity();
ResponseHandler<String> responseHandler = new BasicResponseHandler();
String responseBody = httpclient.execute(httpPost, responseHandler);
System.out.println("Initial credentials ---> "+ responseBody);
System.out.println();
String getresponse = responseBody;
EntityUtils.consume(entity);
} finally {
response.close();
}
}
}

Use Java to get Github repositories

I'm using the following code to send a http request to github.
String url = "https://api.github.com/repositories";
try {
CloseableHttpClient httpClient = HttpClientBuilder.create().build();
HttpPost request = new HttpPost(url);
// StringEntity params = new StringEntity(body);
request.addHeader("content-type", "application/json");
// request.setEntity(params);
HttpResponse result = httpClient.execute(request);
String json = EntityUtils.toString(result.getEntity(), "UTF-8");
System.out.println(json);
} catch (IOException ex) {
}
I got output: {"message":"Not Found","documentation_url":"https://developer.github.com/v3"}
If use directly put "https://api.github.com/repositories" in browser, a lot of useful information will be shown. My question is how can I get the information I see when using browser by using Java.

You should use HttpGet instead of HttpPost. Just like your browser sends a GET request.

HttpPost response doesn't return the json object

I'm currently working on a project which needs to send a post request and get a json object from the server. Earlier I used Get method to access the json object. It worked fine. But because of some server changes I had to move to post method. Then it doesn't return me the json object that I got earlier from the 'get' method. I tried my best to come up with a solution but couldn't. Highly appreciate if anyone can help me to get through this problem.
private AdSniperAdObjectResponse postData(String url) {
//Bundle b = new Bundle();
HttpClient httpClient = HttpClientFactory.getThreadSafeClient();
//Log.d(TAG, "url: " + url);
try {
HttpPost httpPost = new HttpPost(url);
httpPost.setHeader("Content-Type", "application/json");
httpPost.setHeader("Accept", "JSON");
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(4);
nameValuePairs.add(new BasicNameValuePair("latitude", "-33.8736"));
nameValuePairs.add(new BasicNameValuePair("longitude", "151.207"));
nameValuePairs.add(new BasicNameValuePair("age", "35"));
nameValuePairs.add(new BasicNameValuePair("gender", "All"));
httpPost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity resEntity = httpResponse.getEntity();
if (resEntity != null) {
String resp = EntityUtils.toString(resEntity);
Above is the code that I use. Earlier I used HttpGet class. For HttpPost, the 'resp'variable is always null. Don't know what I did wrong.

should't this be like
HttpResponse httpResponse = httpClient.execute(httpPost);
if (httpResponse != null) {
String resp = httpResponse.toString();
and in case if server return JSONString..
say JSONObject data = new JSONObject(resp);
and then get values..

DataContractJsonSerializer jsonSerializer = new DataContractJsonSerializer(typeof (List<NameValuePair> ));
try with this and pass your data using this
jsonSerializer.WriteObject(reqStream, nameValuePairs );
reqStream.Close();
and again deserialize the response whatever you are getting

Before you attempt to get the HttpEntity, you should get the StatusLine and check that the status code is what you expect. I suspect that the real problem is that the server is sending an error response of some kind. And since you used an "Accept" header to request a JSON response, it is likely that the server is not sending any diagnostics in the response body ... so it is empty.

Guys I found the solution. It worked when I commented the following two lines.
httpPost.setHeader("Content-Type", "application/json");
httpPost.setHeader("Accept", "JSON");
So thanks everyone for your answers. Highly appreciate.

Android, Java: HTTP POST Request

I have to do a http post request to a web-service for authenticating the user with username and password. The Web-service guy gave me following information to construct HTTP Post request.
POST /login/dologin HTTP/1.1
Host: webservice.companyname.com
Content-Type: application/x-www-form-urlencoded
Content-Length: 48
id=username&num=password&remember=on&output=xml
The XML Response that i will be getting is
<?xml version="1.0" encoding="ISO-8859-1"?>
<login>
<message><![CDATA[]]></message>
<status><![CDATA[true]]></status>
<Rlo><![CDATA[Username]]></Rlo>
<Rsc><![CDATA[9L99PK1KGKSkfMbcsxvkF0S0UoldJ0SU]]></Rsc>
<Rm><![CDATA[b59031b85bb127661105765722cd3531==AO1YjN5QDM5ITM]]></Rm>
<Rl><![CDATA[username#company.com]]></Rl>
<uid><![CDATA[3539145]]></uid>
<Rmu><![CDATA[f8e8917f7964d4cc7c4c4226f060e3ea]]></Rmu>
</login>
This is what i am doing HttpPost postRequest = new HttpPost(urlString); How do i construct the rest of the parameters?

Here's an example previously found at androidsnippets.com (the site is currently not maintained anymore).
// Create a new HttpClient and Post Header
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://www.yoursite.com/script.php");
try {
// Add your data
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
nameValuePairs.add(new BasicNameValuePair("id", "12345"));
nameValuePairs.add(new BasicNameValuePair("stringdata", "AndDev is Cool!"));
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
// Execute HTTP Post Request
HttpResponse response = httpclient.execute(httppost);
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
} catch (IOException e) {
// TODO Auto-generated catch block
}
So, you can add your parameters as BasicNameValuePair.
An alternative is to use (Http)URLConnection. See also Using java.net.URLConnection to fire and handle HTTP requests. This is actually the preferred method in newer Android versions (Gingerbread+). See also this blog, this developer doc and Android's HttpURLConnection javadoc.

to #BalusC answer I would add how to convert the response in a String:
HttpResponse response = client.execute(request);
HttpEntity entity = response.getEntity();
if (entity != null) {
InputStream instream = entity.getContent();
String result = RestClient.convertStreamToString(instream);
Log.i("Read from server", result);
}
Here is an example of convertStramToString.

Please consider using HttpPost. Adopt from this: http://www.javaworld.com/javatips/jw-javatip34.html
URLConnection connection = new URL("http://webservice.companyname.com/login/dologin").openConnection();
// Http Method becomes POST
connection.setDoOutput(true);
// Encode according to application/x-www-form-urlencoded specification
String content =
"id=" + URLEncoder.encode ("username") +
"&num=" + URLEncoder.encode ("password") +
"&remember=" + URLEncoder.encode ("on") +
"&output=" + URLEncoder.encode ("xml");
connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
// Try this should be the length of you content.
// it is not neccessary equal to 48.
// content.getBytes().length is not neccessarily equal to content.length() if the String contains non ASCII characters.
connection.setRequestProperty("Content-Length", content.getBytes().length);
// Write body
OutputStream output = connection.getOutputStream();
output.write(content.getBytes());
output.close();
You will need to catch the exception yourself.

I'd rather recommend you to use Volley to make GET, PUT, POST... requests.
First, add dependency in your gradle file.
compile 'com.he5ed.lib:volley:android-cts-5.1_r4'
Now, use this code snippet to make requests.
RequestQueue queue = Volley.newRequestQueue(getApplicationContext());
StringRequest postRequest = new StringRequest( com.android.volley.Request.Method.POST, mURL,
new Response.Listener<String>()
{
#Override
public void onResponse(String response) {
// response
Log.d("Response", response);
}
},
new Response.ErrorListener()
{
#Override
public void onErrorResponse(VolleyError error) {
// error
Log.d("Error.Response", error.toString());
}
}
) {
#Override
protected Map<String, String> getParams()
{
Map<String, String> params = new HashMap<String, String>();
//add your parameters here as key-value pairs
params.put("username", username);
params.put("password", password);
return params;
}
};
queue.add(postRequest);

Try HttpClient for Java:
http://hc.apache.org/httpclient-3.x/

You can reuse the implementation I added to ACRA:
http://code.google.com/p/acra/source/browse/tags/REL-3_1_0/CrashReport/src/org/acra/HttpUtils.java?r=236
(See the doPost(Map, Url) method, working over http and https even with self signed certs)

I used the following code to send HTTP POST from my android client app to C# desktop app on my server:
// Create a new HttpClient and Post Header
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://www.yoursite.com/script.php");
try {
// Add your data
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
nameValuePairs.add(new BasicNameValuePair("id", "12345"));
nameValuePairs.add(new BasicNameValuePair("stringdata", "AndDev is Cool!"));
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
// Execute HTTP Post Request
HttpResponse response = httpclient.execute(httppost);
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
} catch (IOException e) {
// TODO Auto-generated catch block
}
I worked on reading the request from a C# app on my server (something like a web server little application).
I managed to read request posted data using the following code:
server = new HttpListener();
server.Prefixes.Add("http://*:50000/");
server.Start();
HttpListenerContext context = server.GetContext();
HttpListenerContext context = obj as HttpListenerContext;
HttpListenerRequest request = context.Request;
StreamReader sr = new StreamReader(request.InputStream);
string str = sr.ReadToEnd();

HTTP request POST in java does not dump the answer?
public class HttpClientExample
{
private final String USER_AGENT = "Mozilla/5.0";
public static void main(String[] args) throws Exception
{
HttpClientExample http = new HttpClientExample();
System.out.println("\nTesting 1 - Send Http POST request");
http.sendPost();
}
// HTTP POST request
private void sendPost() throws Exception {
String url = "http://www.wmtechnology.org/Consultar-RUC/index.jsp";
HttpClient client = new DefaultHttpClient();
HttpPost post = new HttpPost(url);
// add header
post.setHeader("User-Agent", USER_AGENT);
List<NameValuePair> urlParameters = new ArrayList<>();
urlParameters.add(new BasicNameValuePair("accion", "busqueda"));
urlParameters.add(new BasicNameValuePair("modo", "1"));
urlParameters.add(new BasicNameValuePair("nruc", "10469415177"));
post.setEntity(new UrlEncodedFormEntity(urlParameters));
HttpResponse response = client.execute(post);
System.out.println("\nSending 'POST' request to URL : " + url);
System.out.println("Post parameters : " + post.getEntity());
System.out.println("Response Code : " +response.getStatusLine().getStatusCode());
BufferedReader rd = new BufferedReader(new
InputStreamReader(response.getEntity().getContent()));
StringBuilder result = new StringBuilder();
String line = "";
while ((line = rd.readLine()) != null)
{
result.append(line);
System.out.println(line);
}
}
}
This is the web: http://www.wmtechnology.org/Consultar-RUC/index.jsp,from you can consult Ruc without captcha. Your opinions are welcome!