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HTTP Post request and parsing the response in Java

I am trying to create a simple post request to a web API and parse the response received. After quite a lot of search, I was able to come up with the following code:
public class access {
public static void main(String[] args) {
HttpClient httpclient = HttpClients.createDefault();
HttpPost httppost = new HttpPost("https://xxxxx/RSAM_API/api/Logon");
httppost.setHeader("Accept", "application/json");
httppost.setHeader("Content-type", "application/json");
// Request parameters and other properties.
List<NameValuePair> urlParameters = new ArrayList<NameValuePair>(2);
urlParameters.add(new BasicNameValuePair("UserId", "xxxxxx"));
urlParameters.add(new BasicNameValuePair("Password", "xxxxxxx"));
try {
httppost.setEntity(new UrlEncodedFormEntity(urlParameters));
//Execute and get the response.
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
BufferedReader rd = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
String line;
while(null !=(line=rd.readLine())){
System.out.println(line);
}
}
catch (Exception e){
e.printStackTrace();
}
}
}
In the above code, I am doing an post request to the URL login endpoint. the response I see after parsing it is:
An error occurred, please try again or contact the administrator with this error id, 26225
I am able to login to the URL through the browser manually. Not sure where I am going wrong in the code.
Is my approach correct in the first place? Can I be sure that my code is right? If it is, why is the response an error?
Any help would be appreciated. Thank you.

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.

Accessing a login api using http get method in android

I am developing an android app which uses a login api, which will allow its web users to login with their same credentials on the android device.....
the url for the api is
https://api.ecoachsolutions.com/main.php?ecoachsignin=1&server=remote&user=ecoachguest&pass=ecoachguest
which retuns a response in json
JSON object: {
status: <success or error>,
msg: <response message>,
profile: <user profile object>
}
I tried this code which I found searching on the internet but it isn't working,
private void doLogin(View view) {
//ALERT MESSAGE
_spinner.setVisibility(View.VISIBLE);
Toast.makeText(mContext, "connecting to server.... ",
Toast.LENGTH_SHORT).show();
// URLEncode user defined data
String usernameValue = username.getText().toString();
String passValue = password.getText().toString();
// Create http cliient object to send request to server
HttpClient Client = new DefaultHttpClient();
// Create URL string
String URL = "https://api.ecoachsolutions.com/main.php?ecoachsignin=1&server=remote&user="+usernameValue+"&pass="+passValue;
Log.i("httpget", URL);
try
{
String SetServerString ;
// Create Request to server and get response
HttpGet httpget = new HttpGet(URL);
ResponseHandler<String> responseHandler = new BasicResponseHandler();
SetServerString = Client.execute(httpget, responseHandler);
System.out.println(usernameValue);
System.out.println(passValue);
// Show response on activity
Toast.makeText(getBaseContext(),SetServerString,Toast.LENGTH_LONG).show();
}
catch(Exception ex)
{
Toast.makeText(getBaseContext(),"Fail",Toast.LENGTH_LONG).show();
_spinner.setVisibility(View.INVISIBLE);
}
}
will appreciate the help or the positive direction thanks :)

Change your code to get the HttpResponse like below,
String responseBody = "";
HttpResponse response = client.execute(post);
int responseCode = response.getStatusLine().getStatusCode();
Log.i("GET Response Code ",responseCode + "");
switch(responseCode) {
// Means server is responding
case 200:
HttpEntity entity = response.getEntity();
if(entity != null) {
responseBody = EntityUtils.toString(entity);
// Now you can try printing your returned string here, before you go for JSON parsing
}
break;
// Add more case statements to handle other scenarios
}
The code is simple, but if still unable to understand, don't hesitate to ask.

How to send HttpPost every 5 secs

In a Java, I want to send HttpPost every 5 secs without waiting for the response. How can I do that?
I use the following code:
HttpClient httpClient = new DefaultHttpClient();
HttpPost post = new HttpPost(url);
StringEntity params = new StringEntity(json.toString() + "\n");
post.addHeader("content-type", "application/json");
post.setEntity(params);
httpClient.execute(post);
Thread.sleep(5000);
httpClient.execute(post);
but it does not work.
Even though I lose the previous connection and set up a new connection to send the second, the second execute function is always blocked.

Your question leaves a bunch of questions, but the basic point of it can be achieved by:
while(true){ //process executes infinitely. Replace with your own condition
Thread.sleep(5000); // wait five seconds
httpClient.execute(post); //execute your request
}

I tried your code and I got the exception :
java.lang.IllegalStateException: Invalid use of BasicClientConnManager: connection still allocated.
Make sure to release the connection before allocating another one.
This exception is already logged in HttpClient 4.0.1 - how to release connection?
I was able to release the connection by consuming the response with the following code:
public void sendMultipleRequests() throws ClientProtocolException, IOException, InterruptedException {
HttpClient httpClient = new DefaultHttpClient();
HttpPost post = new HttpPost("http://www.google.com");
HttpResponse response = httpClient.execute(post);
HttpEntity entity = response.getEntity();
EntityUtils.consume(entity);
Thread.sleep(5000);
response = httpClient.execute(post);
entity = response.getEntity();
EntityUtils.consume(entity);
}

Using DefaultHttpClient is synchronous which means that program is blocked waiting for the response. Instead of that you could use async-http-client library to perform asynchronous requests (you can download jar files from search.maven.org if you're not familiar with Maven). Sample code may look like:
import com.ning.http.client.*; //imports
try {
AsyncHttpClient asyncHttpClient = new AsyncHttpClient();
while(true) {
asyncHttpClient
.preparePost("http://your.url/")
.addParameter("postVariableName", "postVariableValue")
.execute(); // just execute request and ignore response
System.out.println("Request sent");
Thread.sleep(5000);
}
} catch (Exception e) {
System.out.println("oops..." + e);
}