J2ME Mobile Application Raw Http Call to a Servlet to query Derby Network Server

Part 1: Database

On this part we are going to create a database named employeedb.

1. Run  as Administrator.

2. Type cd %JAVA_HOME%\db\bin & ij.bat to open the Apache Derby CLI.

3. Execute the below commands...

http://pastie.org/4926035

4. Type exit;, to quit.

Part 2: Servlet

On this part we are going to create a servlet named Employee.

1. Run .

2. On the eclipse Juno IDE press Alt + Shift + N then choose .

3. The 'New Dynamic Web Project' dialog will show, name the project as EmployeeInfoWeb, then hit .

3. Accept the defaults, hit .

3. Again accept the defaults, hit .

4. On the 'Project Explorer' right click the , then add new 'Servlet'.

5. The 'Create Servlet' dialog will show, name the servlet as Employee, just hit  to end the wizard.

6. Expand    then add derbyclient.jar and servlet-api.jar, when done hit .

7. Enter the code below...

package com.empinfo;

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class Employee
 */
@WebServlet("/Employee")
public class Employee extends HttpServlet {
 private static final long serialVersionUID = 1L;

    /**
     * Default constructor. 
     */
    public Employee() {
        // TODO Auto-generated constructor stub
    }

 /**
  * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
  */
 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  response.setContentType("text/plain; charset=ISO-8859-1");
  PrintWriter out = response.getWriter();    
  Connection conn = null;
  Statement stmt = null;
  ResultSet rs = null;
  try{
   Class.forName("org.apache.derby.jdbc.ClientDriver").newInstance();
   conn = DriverManager.getConnection("jdbc:derby://localhost:1527/employeedb;");
   stmt = conn.createStatement();
   rs = stmt.executeQuery("SELECT * FROM employee_record WHERE id=" + request.getParameter("id").toString());
   rs.next();
   String fname = rs.getString("fname");
   String lname = rs.getString("lname");      
   out.println(lname + ", " + fname);
   out.close();
  } catch (Exception e) {
   out.println(e.toString());
  }
 }
 

 /**
  * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
  */
 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  // TODO Auto-generated method stub
 }

}

8. Now, On the toolbar click .

9. The 'New' dialog will show, choose 'Server', then hit .

10. On the 'New Server' dialog pick Tomcat v7.0 Server under Apache, then hit .

11. Add the current project to the server, then hit .

12. Start Tomcat!

Part 3: Mobile App

1. Open .

2. Click  to create a new project.

3. On the New Project dialog choose Java ME from the Categories then choose Mobile Application as the project type, then hit .

4. Type EmployeeInfoMobile as project name, then hit .

5. Enter the code below...

package hello;

import java.io.DataInputStream;
import javax.microedition.io.Connector;
import javax.microedition.io.HttpConnection;
import javax.microedition.lcdui.*;
import javax.microedition.midlet.MIDlet;

/**
 * @author Jeremiah G. Gatong
 */
public class Midlet extends MIDlet implements CommandListener {

    private Form f;
    private Command find = new Command("Find", Command.OK, 1);
    private TextField id;
    private StringItem label;

    public void main() {
        f = new Form("Employee Information");
        id = new TextField("Enter ID", "", 25, TextField.ANY);
        label = new StringItem("", "");
        f.append(id);
        f.append(label);
        f.addCommand(find);
        f.setCommandListener(this);
    }

    public void startApp() {
        main();
        Display.getDisplay(this).setCurrent(f);
    }

    public void pauseApp() {
    }

    public void destroyApp(boolean unconditional) {
    }

    public void commandAction(Command c, Displayable d) {
        if (c.equals(find)) {
            StringBuffer sb;
            try {
                String url = "http://localhost:8080/EmployeeInfoWeb/Employee?id=" + id.getString();
                HttpConnection cc = (HttpConnection) Connector.open(url);
                cc.setRequestMethod(HttpConnection.GET);
                cc.setRequestProperty("Content-Type", "text/plain");
                DataInputStream in = (DataInputStream) cc.openDataInputStream();
                int ch;
                sb = new StringBuffer();
                while ((ch = in.read()) != -1) {
                    sb.append((char) ch);
                }
                String str = sb.toString();
                label.setText(str);
            } catch (Exception e) {
                System.err.println("Error :" + e);
            }
        }
    }
}

Output