Java - Sending Http Parameters Via Post Method Easily

Java - sending HTTP parameters via POST method easily

In a GET request, the parameters are sent as part of the URL.

In a POST request, the parameters are sent as a body of the request, after the headers.

To do a POST with HttpURLConnection, you need to write the parameters to the connection after you have opened the connection.

This code should get you started:

String urlParameters  = "param1=a¶m2=b¶m3=c";
byte[] postData       = urlParameters.getBytes( StandardCharsets.UTF_8 );
int    postDataLength = postData.length;
String request        = "http://example.com/index.php";
URL    url            = new URL( request );
HttpURLConnection conn= (HttpURLConnection) url.openConnection();           
conn.setDoOutput( true );
conn.setInstanceFollowRedirects( false );
conn.setRequestMethod( "POST" );
conn.setRequestProperty( "Content-Type", "application/x-www-form-urlencoded"); 
conn.setRequestProperty( "charset", "utf-8");
conn.setRequestProperty( "Content-Length", Integer.toString( postDataLength ));
conn.setUseCaches( false );
try( DataOutputStream wr = new DataOutputStream( conn.getOutputStream())) {
   wr.write( postData );
}

pass parameters via http post method

if i am getting your question correctly , you need to pass your parameters to a web service. in my case i have implemented a method to get the web service response by giving the url and the values as parameters. i think this will help you.

public JSONObject getJSONFromUrl(JSONObject parm,String url) throws JSONException {


         InputStream is = null;
         JSONObject jObj = null;
         String json = "";
        // Making HTTP request
        try {
            // defaultHttpClient
            /*JSONObject parm = new JSONObject();
            parm.put("agencyId", 27);
            parm.put("caregiverPersonId", 47);*/

        /*  if(!(jObj.isNull("d"))){
                jObj=null;
            }
            */


            DefaultHttpClient httpClient = new DefaultHttpClient();
            HttpPost httpPost = new HttpPost(url);

            httpPost.addHeader("Content-Type", "application/json; charset=utf-8");
            HttpEntity body = new StringEntity(parm.toString(), "utf8");
            httpPost.setEntity(body);
            HttpResponse httpResponse = httpClient.execute(httpPost);
            HttpEntity httpEntity = httpResponse.getEntity();

            is = httpEntity.getContent();          

               /* String response = EntityUtils.toString(httpEntity);
                Log.w("myApp", response);*/

        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        try {
            BufferedReader reader = new BufferedReader(new InputStreamReader(
                    is, "iso-8859-1"), 8);
            StringBuilder sb = new StringBuilder();
            String line = null;
            while ((line = reader.readLine()) != null) {
                sb.append(line + "\n");
            }
            is.close();
            json = sb.toString();
        } catch (Exception e) {
            Log.e("Buffer Error", "Error converting result " + e.toString());
        }

     //   JSONObject jObj2 = new JSONObject(json);
        // try parse the string to a JSON object
        try {
             jObj = new JSONObject(json);
        } catch (JSONException e) {
            Log.e("JSON Parser", "Error parsing data " + e.toString());
        }

        // return JSON String
        return jObj;

    }

this method take two parameters. one is the url, other one is the values that we should send to the web service. and simply returns the json object. hope this will help you

EDIT

to pass your username and password just use below code

    JsonParser jp = new JsonParser();  // create instance for the jsonparse class

    String caregiverID = MainActivity.confirm.toString();

    JSONObject param = new JSONObject();
    JSONObject job =  new JSONObject();
    try {
        param.put("username", yourUserNAme);
        job = jp.getJSONFromUrl(param, yourURL);

How to add parameters to HttpURLConnection using POST using NameValuePair

You can get output stream for the connection and write the parameter query string to it.

URL url = new URL("http://yoururl.com");
HttpsURLConnection conn = (HttpsURLConnection) url.openConnection();
conn.setReadTimeout(10000);
conn.setConnectTimeout(15000);
conn.setRequestMethod("POST");
conn.setDoInput(true);
conn.setDoOutput(true);

List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("firstParam", paramValue1));
params.add(new BasicNameValuePair("secondParam", paramValue2));
params.add(new BasicNameValuePair("thirdParam", paramValue3));

OutputStream os = conn.getOutputStream();
BufferedWriter writer = new BufferedWriter(
        new OutputStreamWriter(os, "UTF-8"));
writer.write(getQuery(params));
writer.flush();
writer.close();
os.close();

conn.connect();

...

private String getQuery(List<NameValuePair> params) throws UnsupportedEncodingException
{
    StringBuilder result = new StringBuilder();
    boolean first = true;

    for (NameValuePair pair : params)
    {
        if (first)
            first = false;
        else
            result.append("&");

        result.append(URLEncoder.encode(pair.getName(), "UTF-8"));
        result.append("=");
        result.append(URLEncoder.encode(pair.getValue(), "UTF-8"));
    }

    return result.toString();
}

How to send simple http post request with post parameters in java

HTTP POST request example using Apache HttpClient v.4.x

HttpClient httpClient = HttpClients.createDefault();
HttpPost httpPost = new HttpPost(url);
MultipartEntityBuilder builder = MultipartEntityBuilder.create();
builder.addTextBody("param1", param1Value, ContentType.TEXT_PLAIN);
builder.addTextBody("param2", param2Value, ContentType.TEXT_PLAIN);
HttpEntity multipart = builder.build();
httpPost.setEntity(multipart);
HttpResponse response = httpClient.execute(httpMethod);

make an HttpsURLConnection request with parameters by method post

You are wrong on the line

wr.writeBytes(parameter.toString());

because parameter.toString() returns string like [[Ljava.lang.String;@1f554b06 instead of expected param1=value1¶m2=value2 etc.

So correct this part to

    String parameterString = Arrays.stream(parameter)
            .map(pair -> pair[0] + "=" + pair[1])
            .collect(Collectors.joining("&"));
    wr.writeBytes(parameter.toString());

Sending parameters with a @POST request in java client

Please try the below format.

String input = "{\"name\":\"tom\",\"email\":\"tom@email.com\"}";

ClientResponse response = webResource.type("application/json")
       .post(ClientResponse.class, input);

Can't pass request parameters using http post

URL dos not work with spaces.From your code above: " &exportDiscardRec="
To avoid such issues use URIBuilder or something similar if possible.

Now for the request, you are not building your request correctly for example you do not provide the body.
Check below example:

    Map<String, String> colMapObj = new HashMap<>();
    colMapObj.put("testKey", "testdata");

    CloseableHttpClient client = HttpClients.createDefault();
    HttpPost httpPost = new HttpPost(url);

    JSONObject body = new JSONObject(colMapObj);
    StringEntity entity = new StringEntity(body.toString());
    httpPost.setEntity(entity);
    httpPost.setHeader("Accept", "application/json");
    httpPost.setHeader("Content-type", "application/json");

    CloseableHttpResponse response = client.execute(httpPost);
    System.out.println(response.getEntity().toString());
    client.close();

More examples just google "apache http client post examples" (e.g. http://www.baeldung.com/httpclient-post-http-request)

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