Multipart POST file upload

gistfile1.java

public static void uploadFile(String urlString, Map<String, String> params, String fileName, InputStream fileInputStream) {
    String lineEnd = "\r\n";
    String twoHyphens = "--";
    String boundary = "*****";
    HttpURLConnection conn;
	try {
        // ------------------ CLIENT REQUEST
        Log.e(Tag, "Inside second Method");
        // open a URL connection to the Servlet
        URL url = new URL(urlString);
        // Open a HTTP connection to the URL
        conn = (HttpURLConnection) url.openConnection();
        // Allow Inputs
        conn.setDoInput(true);
        // Allow Outputs
        conn.setDoOutput(true);
        // Don't use a cached copy.
        conn.setUseCaches(false);
        // Use a post method.
        conn.setRequestMethod("POST");
        conn.setRequestProperty("Connection", "Keep-Alive");
        conn.setRequestProperty("Content-Type", "multipart/form-data;boundary=" + boundary);

        DataOutputStream dos = new DataOutputStream(conn.getOutputStream());

        for (Entry<String, String> e : params.entrySet()) {
        	dos.writeBytes(twoHyphens + boundary + lineEnd);
        	dos.writeBytes("Content-Disposition: form-data; name=\""+e.getKey()+"\"" + lineEnd);
        	dos.writeBytes(lineEnd);
        	dos.writeBytes(e.getValue());
        	dos.writeBytes(lineEnd);
        }
            
        dos.writeBytes(twoHyphens + boundary + lineEnd);
        dos.writeBytes("Content-Disposition: post-data; name=\"catlog\";filename=\"" + fileName + "\"" + lineEnd);
        dos.writeBytes(lineEnd);
        Log.e(Tag, "Headers are written");
        // create a buffer of maximum size

        int bytesAvailable = fileInputStream.available();
        int maxBufferSize = 1000;
        // int bufferSize = Math.min(bytesAvailable, maxBufferSize);
        byte[] buffer = new byte[bytesAvailable];

        // read file and write it into form...

        int bytesRead = fileInputStream.read(buffer, 0, bytesAvailable);

        while (bytesRead > 0) {
        	dos.write(buffer, 0, bytesAvailable);
            bytesAvailable = fileInputStream.available();
            bytesAvailable = Math.min(bytesAvailable, maxBufferSize);
            bytesRead = fileInputStream.read(buffer, 0, bytesAvailable);
        }
        // send multipart form data necesssary after file data...
        dos.writeBytes(lineEnd);
        dos.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd);
        // close streams
        Log.e(Tag, "File is written");
        fileInputStream.close();
        dos.flush();
        dos.close();
   		int code = conn.getResponseCode();
    } catch (MalformedURLException ex) {
        Log.e(Tag, "error: " + ex.getMessage(), ex);
    } catch (IOException ioe) {
        Log.e(Tag, "error: " + ioe.getMessage(), ioe);
    }
}