请在下面找到一个示例。这将对某人有所帮助。它在诺基亚 Asha 501 中进行了测试，运行良好。
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
import javax.microedition.io.*;
import java.io.*;
public class GetNpost extends MIDlet implements CommandListener
{
private Display display; // Reference to Display object
private Form fmMain; // The main form
private Alert alError; // Alert to error message
private Command cmGET; // Request method GET
private Command cmPOST; // Request method Post
private Command cmExit; // Command to exit the MIDlet
private TextField tfAcct; // Get account number
private TextField tfPwd; // Get password
private StringItem siBalance;// Show account balance
private String errorMsg = null;
GetNetworkConnection getObject = null;
PostNetworkConnection postObject = null;
GetNpost mainObject = null;
public GetNpost()
{
display = Display.getDisplay(this);
mainObject = this;
// Create commands
cmGET = new Command("GET", Command.SCREEN, 2);
cmPOST = new Command("POST", Command.SCREEN, 3);
cmExit = new Command("Exit", Command.EXIT, 1);
// Textfields
tfAcct = new TextField("Account:", "", 5, TextField.NUMERIC);
tfPwd = new TextField("Password:", "", 10, TextField.ANY | TextField.PASSWORD);
// Balance string item
siBalance = new StringItem("Balance: $", "");
// Create Form, add commands & componenets, listen for events
fmMain = new Form("Account Information");
fmMain.addCommand(cmExit);
fmMain.addCommand(cmGET);
fmMain.addCommand(cmPOST);
fmMain.append(tfAcct);
fmMain.append(tfPwd);
fmMain.append(siBalance);
fmMain.setCommandListener(this);
}
public void startApp()
{
display.setCurrent(fmMain);
}
public void pauseApp()
{ }
public void destroyApp(boolean unconditional)
{ }
public void commandAction(Command c, Displayable s)
{
if (c == cmGET || c == cmPOST)
{
try
{
if (c == cmGET){
getObject = new GetNetworkConnection();
getObject.start();
}
else{
postObject = new PostNetworkConnection();
postObject.start();
}
}
catch (Exception e)
{
System.err.println("Msg: " + e.toString());
}
}
else if (c == cmExit)
{
destroyApp(false);
notifyDestroyed();
}
}
/*--------------------------------------------------
* Access servlet using GET
*-------------------------------------------------*/
private void lookupBalance_withGET() throws IOException
{
HttpConnection http = null;
InputStream iStrm = null;
boolean ret = false;
// Data is passed at the end of url for GET
// don't use localhost as a ip
String url = "http://(ip address):(port)/ServerSide/hello" + "?" +
"account=" + tfAcct.getString() + "&" +
"password=" + tfPwd.getString();
try
{
http = (HttpConnection) Connector.open(url);
//----------------
// Client Request
//----------------
// 1) Send request method
http.setRequestMethod(HttpConnection.GET);
// 2) Send header information - none
// 3) Send body/data - data is at the end of URL
//----------------
// Server Response
//----------------
iStrm = http.openInputStream();
// Three steps are processed in this method call
ret = processServerResponse(http, iStrm);
}
finally
{
// Clean up
if (iStrm != null)
iStrm.close();
if (http != null)
http.close();
}
// Process request failed, show alert
if (ret == false)
showAlert(errorMsg);
}
/*--------------------------------------------------
* Access servlet using POST
*-------------------------------------------------*/
private void lookupBalance_withPOST() throws IOException
{
HttpConnection http = null;
OutputStream oStrm = null;
InputStream iStrm = null;
boolean ret = false;
// Data is passed as a separate stream for POST (below)
// don't use localhost as a ip
String url = "http://(ip address):(port)/ServerSide/hello";
try
{
http = (HttpConnection) Connector.open(url);
//----------------
// Client Request
//----------------
// 1) Send request type
http.setRequestMethod(HttpConnection.POST);
// 2) Send header information. Required for POST to work!
http.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
oStrm = http.openOutputStream();
// If you experience connection/IO problems, try
// removing the comment from the following line
// http.setRequestProperty("Connection", "close");
// 3) Send data/body
// Write account number
byte data[] = ("account=" + tfAcct.getString()).getBytes();
oStrm.write(data);
// Write password
data = ("&password=" + tfPwd.getString()).getBytes();
oStrm.write(data);
// For 1.0.3 remove flush command
// See the note at the bottom of this file
// oStrm.flush();
//----------------
// Server Response
//----------------
iStrm = http.openInputStream();
// Three steps are processed in this method call
ret = processServerResponse(http, iStrm);
}
catch(Exception e){
System.out.println("Error in Post: "+e.getMessage());
}
finally
{
// Clean up
if (iStrm != null)
iStrm.close();
if (oStrm != null)
oStrm.close();
if (http != null)
http.close();
}
// Process request failed, show alert
if (ret == false)
showAlert(errorMsg);
}
/*--------------------------------------------------
* Process a response from a server
*-------------------------------------------------*/
private boolean processServerResponse(HttpConnection http, InputStream iStrm) throws IOException
{
//Reset error message
errorMsg = null;
// 1) Get status Line
if (http.getResponseCode() == HttpConnection.HTTP_OK)
{
// 2) Get header information - none
// 3) Get body (data)
int length = (int) http.getLength();
String str;
if (length != -1)
{
byte servletData[] = new byte[length];
iStrm.read(servletData);
str = new String(servletData);
}
else // Length not available...
{
ByteArrayOutputStream bStrm = new ByteArrayOutputStream();
int ch;
while ((ch = iStrm.read()) != -1)
bStrm.write(ch);
str = new String(bStrm.toByteArray());
bStrm.close();
}
// Update the string item on the display
siBalance.setText(str);
return true;
}
else
// Use message from the servlet
errorMsg = new String( http.getResponseMessage());
return false;
}
/*--------------------------------------------------
* Show an Alert
*-------------------------------------------------*/
private void showAlert(String msg)
{
// Create Alert, use message returned from servlet
alError = new Alert("Error", msg, null, AlertType.ERROR);
// Set Alert to type Modal
alError.setTimeout(Alert.FOREVER);
// Display the Alert. Once dismissed, display the form
display.setCurrent(alError, fmMain);
}
public class GetNetworkConnection extends Thread{
public void run(){
try {
mainObject.lookupBalance_withGET();
}
catch(Exception e){
System.out.println("Error in Get Connection: "+e.getMessage());
}
}
}
public class PostNetworkConnection extends Thread{
public void run(){
try {
mainObject.lookupBalance_withPOST();
}
catch(Exception e){
System.out.println("Error in Post Connection: "+e.getMessage());
}
}
}
}
服务器端代码是，（它是一个servlet。名称是hello.java）
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
*
* @author thirumalvalavan
*/
@WebServlet(name = "hello", urlPatterns = {"/hello"})
public class hello extends HttpServlet {
/**
* Processes requests for both HTTP <code>GET</code> and <code>POST</code> methods.
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
try {
// /*TODO output your page here
out.println("<html>");
out.println("<head>");
out.println("<title>Servlet hello</title>");
out.println("</head>");
out.println("<body>");
out.println("<h1>Servlet hello at " + request.getContextPath() + "</h1>");
out.println("</body>");
out.println("</html>");
// */
} finally {
out.close();
}
}
// <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
/**
* Handles the HTTP <code>GET</code> method.
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// processRequest(request, response);
String acct = request.getParameter("account"),
pwd = request.getParameter("password");
System.out.println("Hello Get Method::: " + acct + " " + pwd);
PrintWriter out = response.getWriter();
out.println("<html>");
out.println("<head>");
out.println("<title>Servlet hello</title>");
out.println("</head>");
out.println("<body>");
out.print("<h1>Hi Get Method: </h1> <br> <h2> Your Account is: " + acct + "<br> Your pwd is: " + pwd + "</h2>");
out.println("</body>");
out.println("</html>");
out.close();
}
/**
* Handles the HTTP <code>POST</code> method.
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// processRequest(request, response);
String acct = request.getParameter("account"),
pwd = request.getParameter("password");
System.out.println("Hello Post Method::: " + acct + " " + pwd);
response.setContentType("text/plain");
PrintWriter out = response.getWriter();
out.println("<html>");
out.println("<head>");
out.println("<title>Servlet hello</title>");
out.println("</head>");
out.println("<body>");
out.print("<h1>Hi Post Method: </h1> <br> <h2> Your Account is: " + acct + "<br> Your pwd is: " + pwd + "</h2>");
out.println("</body>");
out.println("</html>");
out.close();
}
/**
* Returns a short description of the servlet.
* @return a String containing servlet description
*/
@Override
public String getServletInfo() {
return "Short description";
}// </editor-fold>
}