GPRS + J2ME Related queires

[Trupti Mehta]

Hello,

I have developed a pure J2ME application and its working on any mobile phone with any platform. Now I got to implement SMS feature, and add details of a form in a file on the server. For this I will nedd GPRS.

I don't know how to implement this. can I assign attributes like "method="POST" action=urlToServlet" in a J2ME form and call a Servlet to do the saving in a file on server. OR implement HttpConnection directly on OK button of the form.
I also need to check up if the phone has GPRS access or not, if Yes, then connect to Internet and then proceed.

And Yes, after implementing GPRS feature, will the application run on all platforms like its wokring now on Windows Mobile, Blackberry, Symbian, etc.

Can you please guide me what to do and how to do the same. Try to help at your earliest.

Thanks.

[Ahmed Abdul Baqi]

    [quote=Trupti Mehta]Hello, 

    I have developed a pure J2ME application and its working on any mobile phone with any platform. Now I got to implement SMS feature, and add details of a form in a file on the server. For this I will nedd GPRS. 
 
   I don't know how to implement this. can I assign attributes like "method="POST" action=urlToServlet" in a J2ME form and call a Servlet to do the saving in a file on server. OR implement HttpConnection directly on OK button of the form. 
  I also need to check up if the phone has GPRS access or not, if Yes, then connect to Internet and then proceed. 

  And Yes, after implementing GPRS feature, will the application run on all platforms like its wokring now on Windows Mobile, Blackberry, Symbian, etc.

  Can you please guide me what to do and how to do the same.  Try to help at your earliest.

  Thanks.[/quote]


<code>
private void checkLogin() {
try {
	String request = "";
	String str = "";
	request = null;
	str = "";
	/*here u can assign the url on which ur servlet is hosted and send the request*/
                String url = "http://localhost:8080/form1/checklogin";
	System.out.println(" the url is :: " + url);
	con = (StreamConnection) Connector.open(url);
	os = con.openOutputStream();
	int i = 0;
	
                un = Uname.getString();
	p = pwd.getString();
	request = un + "#" + p + "#";
	byte b[] = request.getBytes();
	System.out.println(request);
	for (i = 0; i < b.length; i++) {
	      os.write(b[i]);
	}
	os.close();
	System.out.println("here is ");
	in = con.openInputStream();
	while ((i = in.read()) != -1) {
	      char ch = (char) i;
	      str = str + ch;
	}
	System.out.println(str);
	if (str.equals("TRUE")) {
		Alert a = new Alert("The Following Details are valid","connected ", img, AlertType.ALARM);
		display.setCurrent(a);
		System.out.println("You are a valid user.......");
	} else {
		Alert a = new Alert("The Following Details are Invalid",
		"Invalid Login/Password ", img, AlertType.ALARM);
		display.setCurrent(a);
	}
	in.close();
	} catch (Exception e) {
	}
	the above methd i have declared in the run method and in the Command Action Listener method you can call that thread for any key Event or for any Button.

here i have writen a simple method called check login where i am retreiving uname and password from a text box in my MIDlet and saving the text in two string variables and passing the two string as a request along with the url to the server.See GPRS is a Telecom - General Packet Radio Service that uses the http protocol to send and receive data.Almost all basic j2me devices will have GPRS facility.You just need to check with your service prvider wether GPRS is activated on the mobile or not. 

public class ConnectionNotFoundException
extends IOException
can be given to check if the device supports the type of connection you have given.yes you can create a cod file of ur succesffully running jad and jar for blackberry and check wether the application gets the connection or not.


Thanks.

[Trupti Mehta]

Ahmed Abdul Baqi wrote:

   

<code>
private void checkLogin() {
try {
	String request = "";
	String str = "";
	request = null;
	str = "";
	/*here u can assign the url on which ur servlet is hosted and send the request*/
                String url = "http://localhost:8080/form1/checklogin";
	System.out.println(" the url is :: " + url);
	con = (StreamConnection) Connector.open(url);
	os = con.openOutputStream();
	int i = 0;
	
                un = Uname.getString();
	p = pwd.getString();
	request = un + "#" + p + "#";
	byte b[] = request.getBytes();
	System.out.println(request);
	for (i = 0; i < b.length; i++) {
	      os.write(b[i]);
	}
	os.close();
	System.out.println("here is ");
	in = con.openInputStream();
	while ((i = in.read()) != -1) {
	      char ch = (char) i;
	      str = str + ch;
	}
	System.out.println(str);
	if (str.equals("TRUE")) {
		Alert a = new Alert("The Following Details are valid","connected ", img, AlertType.ALARM);
		display.setCurrent(a);
		System.out.println("You are a valid user.......");
	} else {
		Alert a = new Alert("The Following Details are Invalid",
		"Invalid Login/Password ", img, AlertType.ALARM);
		display.setCurrent(a);
	}
	in.close();
	} catch (Exception e) {
	}
	the above methd i have declared in the run method and in the Command Action Listener method you can call that thread for any key Event or for any Button.

here i have writen a simple method called check login where i am retreiving uname and password from a text box in my MIDlet and saving the text in two string variables and passing the two string as a request along with the url to the server.See GPRS is a Telecom - General Packet Radio Service that uses the http protocol to send and receive data.Almost all basic j2me devices will have GPRS facility.You just need to check with your service prvider wether GPRS is activated on the mobile or not. 

public class ConnectionNotFoundException
extends IOException
can be given to check if the device supports the type of connection you have given.yes you can create a cod file of ur succesffully running jad and jar for blackberry and check wether the application gets the connection or not.


Thanks.

Thanks Ahmed. But things are a bit confusing for me, it would be better if you can solve it.
You get connected to a servlet lying on web server. Then you open outputstream, add username and password to request and writing your request into bytes using the outputstream. Similarly with input sream you are reading till end of file.
> passing the two string as a request along with the url to the server
I am not understanding what exactly and how you are doing.

I also retrieve data from textFields of a form, and have to save them to a file lying on the server. Can you help me code how do I do this? Pass the parameters to the Servlet and do file saving operation in the servlet or directly access the fie lying on the server and save the details. Which option is better and how to code it? I can't make out and am confused.

Would be greatful if you can help me out.

Thanks

[Ahmed Abdul Baqi]

Thanks Ahmed. But things are a bit confusing for me, it would be better if you can solve it.
You get connected to a servlet lying on web server. Then you open outputstream, add username and password to request and writing your request into bytes using the outputstream. Similarly with input sream you are reading till end of file.
> passing the two string as a request along with the url to the server
I am not understanding what exactly and how you are doing.

I also retrieve data from textFields of a form, and have to save them to a file lying on the server. Can you help me code how do I do this? Pass the parameters to the Servlet and do file saving operation in the servlet or directly access the fie lying on the server and save the details. Which option is better and how to code it? I can't make out and am confused.

Would be greatful if you can help me out.

Thanks

import java.io.*;
import javax.microedition.io.*;
import javax.microedition.lcdui.*;
import javax.microedition.midlet.*;

public class Iecform1 extends MIDlet implements CommandListener, Runnable {
	/*
	 * Here we will Declare the form,commands,text fields,Connection Input
	 * Output Stream,thread variables and display object.
	 */
	private static Form loginForm;
	private Command login;
	private Command exit;
	private static Display display;
	private TextField Uname;
	private TextField pwd;
	int i;
	OutputStream os;
	InputStream in;
	StreamConnection con;
	String un;
	String p;
	Thread th;
	Image img;
	int servlet;

	/*
	 * Initializing variables and display object inside the constructor
	 * 
	 */
	public Iecform1() {
		i = 0;
		con = null;
		un = "";
		p = "";
		servlet = 0;
		try {
			loginForm = new Form("LOGIN");
			login = new Command("LOGIN", 4, 1);
			exit = new Command("EXIT", 7, 2);
			Uname = new TextField("LOGIN:", "", 20, 0);
			pwd = new TextField("PASSWORD:", "", 20, 0x10000);

			img = Image.createImage("/d8.png");
			display = Display.getDisplay(this);
		} catch (Exception e) {
			System.err.println("Constructor error:" + e);
		}
	}

	protected void destroyApp(boolean arg0) throws MIDletStateChangeException {
		notifyDestroyed();

	}

	protected void pauseApp() {
		// TODO Auto-generated method stub

	}

	/*
	 * When MIDlet is loaded we are appending the Display objects to the Form
	 * Set the command Listener to the Form and set the loginForm as Displayable
	 * 
	 * @see javax.microedition.midlet.MIDlet#startApp()
	 */
	protected void startApp() throws MIDletStateChangeException {
		try {
			loginForm.append(Uname);
			loginForm.append(img);
			loginForm.append(pwd);
			loginForm.addCommand(login);
			loginForm.addCommand(exit);
			loginForm.setCommandListener(this);
			display.setCurrent(loginForm);
		} catch (NullPointerException e) {
			System.err.println(e + "start asf");
		}
	}

	public void commandAction(Command cmd, Displayable dis) {
		if (dis == loginForm) {
			if (cmd == login) {
				//if (!un.equals("") && !p.equals("")) {
					try {
						/*
						 * Instantiating the Thread object in the memory and
						 * calling the run method
						 */

						servlet = 1;
						th = new Thread(this);
						th.start();

					} catch (Exception e) {
						System.out.println(e);
					}
					System.out.println("Data is sent to Server.....");
				}

			//} else {

			//	Alert a = new Alert("Uname and pwd empty", null, null, null);
			//	display.setCurrent(a);
			//}
			if (cmd == exit) {
				try {
					/*
					 * If Exit Key is Pressed the Application will call
					 * destroyApp and exit the Application.
					 */
					destroyApp(true);
				} catch (MIDletStateChangeException e) {
					e.printStackTrace();
				}
				notifyDestroyed();
			}
		}
	}

	/*
	 * This method will Open the URL connection and send the request using
	 * OutputStream The User Name and password from the Text Input control is
	 * concatenated and sent as a request by writing it into a byte array and
	 * response from the server is read using the InputStream and compared.
	 */
	private void checkLogin() {
		try {
			String request = "";
			String str = "";
			request = null;
			str = "";
			String url = "http://localhost:8080/form1/checklogin";
			System.out.println(" the url is :: " + url);
			con = (StreamConnection) Connector.open(url);
			os = con.openOutputStream();
			int i = 0;
			un = Uname.getString();
			p = pwd.getString();
			request = un + "#" + p + "#";
			byte b[] = request.getBytes();
			System.out.println(request);
			for (i = 0; i < b.length; i++) {
				os.write(b[i]);
			}
			os.close();
			System.out.println("here is ");
			in = con.openInputStream();
			while ((i = in.read()) != -1) {
				char ch = (char) i;
				str = str + ch;
			}
			System.out.println(str);
			if (str.equals("TRUE")) {
				Alert a = new Alert("The Following Details are valid",
						"connected ", img, AlertType.ALARM);
				display.setCurrent(a);
				System.out.println("You are a valid user.......");
			} else {
				Alert a = new Alert("The Following Details are Invalid",
						"Invalid Login/Password ", img, AlertType.ALARM);
				display.setCurrent(a);
			}
			in.close();
		} catch (Exception e) {
		}
	}

	public void run() {
		/***********************************************************************
		 * Assigning the task of Network connection to the thread
		 */

		if (servlet == 1) {

			checkLogin();
			System.out.println(" in checking login run()" + un);

		}
		try {
			os.close();
			con.close();
		} catch (Exception e) {
		}
	}
}
    

this is the midlet copy and paste it in the eclipse ide or editplus...read the commments

The servlet part just create a folder and run this servlet on your local system read the comments

 
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.sql.*;
import java.lang.*;
import java.util.*;

public class CheckLogin extends HttpServlet{
	/* Declaring the variables,InputStream,OutputStream,Conection variables and arrays.
	*/
	ServletInputStream  sin;
	ServletOutputStream sos=null;
	Connection con;
	String p[]=null,str="",response="";
	byte[] b;
	char ch;
	int i,j,k=0;
	public void init(ServletConfig scon) throws ServletException{
	    try	{
		    super.init(scon);
			System.out.println("connected............!");
		}
		catch(Exception e){
			System.out.println(e);
		}
	}
	/* Using doGet method of HttpServletInterface we will Send and receive request and Response from the MIDlet.
	*/
	public void doGet(HttpServletRequest req,HttpServletResponse res) throws ServletException,IOException{
			try{
				res.setContentType("text/plain");
				sin=req.getInputStream();
				str="";
				while((i=sin.read())!=-1){
					ch=(char)i;
					str=str+ch;
				}
				System.out.println("Received Stream From MIDlet="+str);
				str.trim();
				String[] ele = str.split("#");
				System.out.println("length"+ele.length);
				for (k=0;k<ele.length;k++){
					System.out.println("Elements are " +ele[k]+" k is "+k);
				}
				System.out.println(ele[0]+ele[1]);
				response=ele[1];
				response.trim();
				sos=res.getOutputStream();
				/*Here the response from MIDet is compared using equals() method*/		
				if ("BAQI".equals(response))
					sos.print("TRUE");
				else
				   sos.print("FALSE");
			}catch (Exception e){
				e.printStackTrace();
				System.out.println("null pointer\n");
			}
		}
		public void destroy(){
			try{
				sos.close();
				sin.close();
				con.close();				
			}catch(Exception e){
				System.out.println("end"+e);
			}
		}
}   

Let me know if you are able to understand

>

[Trupti Mehta]

Oh Ahmed, Thanks for this help. I wrote a servlet to save the contents in a file over the server and it is working perfectly (atleast with emulator).

But am facing coupl of problems. My Servlet code - that passes "success" or "failure":-

        response.setContentType("text/plain");
        String complainLine = "";  // request.getParameter("compDetails");
        String result = "failure";
        int i=0;
        char ch;
        try {
            // Receive from Midlet
            ServletInputStream sin = request.getInputStream();
            while ( (i = sin.read()) != -1) {
                ch = (char)i;
                complainLine = complainLine+ch;
            }

            // Write to the file
            String fileName = "complains.txt";
            File outputFile = new File(fileName);
            FileWriter fout = new FileWriter(outputFile);
            fout.write(complainLine+"\n");
            fout.close();
            result = "success";

            response.setStatus(HttpServletResponse.SC_OK);
            ServletOutputStream sos = response.getOutputStream();
            sos.println(result);
            sos.close();
        } catch(Exception e) {
            System.out.println("failure : " + e.getMessage());
        }

Midlet Code that reads the servlet response :

                .....
                System.out.println("here is ");   
                in = con.openInputStream();   
                while ((i = in.read()) != -1) {   
                    char ch = (char) i;   
                    str = str + ch;   
                }   
                System.out.println(str);   
                if (str.equals("success")) {   
                    smsForm = null;
                    Alert a = new Alert("Complain send successfully",   
                            "Send Successfully ", null, AlertType.ALARM);   
                    display.setCurrent(a, menuList);   // After alert go to mnuList display
                    System.out.println("Send Completed.......");   
                } else {   
                    Alert a = new Alert("Problem sending details",   
                            "Error occured ", null, AlertType.ALARM);   
                    display.setCurrent(a);   
                }   



/*********** COMMAND LISTENER CODE ******************
                                } else if (smsForm.getTask().equals("G")) {
                                    servlet = 1;
                                    try {
                                        th = new Thread(this);
                                        th.start();
                                    } catch(Exception e) {
                                        System.out.println("Exception with GPRS: " + e);
                                    }
                                    
                                    System.out.println("Data Sent To Server .....");
                                }

The problem is on results of servlet, I see the original form only, and not the alert that have added for "Success" or "Failure" message. From System.out.println, I came to know that its a success amd checked the file, data was added. So came to know. Can you point out where am I wrong which makes it go to the form back instead of alert.

[Ahmed Abdul Baqi]

do one thing on the servlet side send a response to the midlet if it is success or fialure and read the response on the midlet you are giving the failure in the exception it is not necessary that every time there will be an exception....so as the file is sent to the server send a success and if not send then send a failure and keep the whole code in try.....so save the response from the midlet that you are reading in a variable and check if that variable is empty or not if it is empty than send the response from the servlet as failure and if it is not null then send as success.....that will solve your problem....

[Trupti Mehta]

Right Ahmed. Why that simple thought didn't come in my mind?

Thanks a lot.

Ahmed, can you help me guide on https://coderanch.com/t/443507/Java-Micro-Edition/Mobile/Sending-SMS-form-J2ME" target="_blank" rel="nofollow">Sending SMS from J2ME query also.