J2ME vs WAP ?

Question

Hi,
I am starting on wireless, but I have a question about the difference to develop a WAP application (WEB server + JSP + WML) that the user can access from their device (PDA, Cell phone) in order to access some resources vs. develop an application with J2ME(MIDP)?
The J2ME app, is loaded into the device?
How the resources is access (eg. database,etc), from a WAP app we could create a servlet in order to query a database, in J2ME/MIDP is possible to get access also?
Thanks in advance!

Answer 1

Hi,
Yes, you can to use the servlet also to develop your J2ME application but it is some difference vs WAP application. You can to implement the doPost method in the Servlet class and also can to read the string command send for the J2ME client. For example you can to use:
public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
StringBuffer messagebuffer=new StringBuffer("");
byte ch;
char c;
ServletInputStream in = request.getInputStream();
DataInputStream din = new DataInputStream(in );
while ((ch =din.readByte()) != -1){
messagebuffer.append((char) ch);
c=(char) ch;
if(c=='$') break;
String req=messagebuffer.toString();
//req is the command from client
//your code
//send the response to J2ME client
response.setStatus( response.SC_OK );
ServletOutputStream servletout = response.getOutputStream();
DataOutputStream ot=new DataOutputStream(servletout);
ot.writeBytes(res);
ot.flush();
ot.close();
servletout.close();
From client you need to make the connection to this Servlet and also need to send the request for this Servlet(follow by $). Out, this can work like the WAP application, but you have also more options. In the Servlet you can to connect to the database, or to the other device to form the J2ME client response.
hope you help
Sorry for my bad english
Calin