Enviando e-mail de dispositivos J2ME

Enviando e-mail de dispositivos J2ME

Quando voc� envia um e-mail, voc� conecta um usu�rio com um servidor que suporta o Simple Mail Transfer Protocol (smtp). Um MIDLet conecta com o servidor atrav�s do protocolo http. Para enviar um e-mail, � necess�rio codificiar um servlet hospedado em um web server. Midlet envia e recebe dados do servlet.

O exemplo abaixo envia um e-mail a partir de dispositivos J2ME:

import javax.microedition.lcdui.*;
import javax.microedition.midlet.MIDlet;
import javax.microedition.midlet.MIDletStateChangeException;
import javax.microedition.io.*;
import java.io.InputStream;
import java.io.PrintStream;

public class SendMail extends MIDlet implements CommandListener {

private String MAIL_SERVER_URL = 
"http://localhost:8080/examples/servlet/SendMailServlet?";
Display display = null;
List dmenu = null;
TextBox input = null;
TextBox to =null;
TextBox msg =null;
String user = null;
int status =0;
Command backCommand = new Command("Back", Command.BACK, 0);
Command submitCommand = new Command("Submit", Command.OK, 2);
Command exitCommand = new Command("Exit", Command.STOP, 3);
Command okCommand = new Command("OK", Command.OK, 0);
String url = MAIL_SERVER_URL + "u=" + user;

public SendMail() { }

public void startApp() throws MIDletStateChangeException {
display = Display.getDisplay(this);
displayMenu();
}

public void pauseApp() { }

public void destroyApp(boolean unconditional) {
notifyDestroyed();
}

public void commandAction(Command c, Displayable d) {
if(c == exitCommand ) {
destroyApp(true);
} else if (c == backCommand) {
displayMenu();
} else if (c == submitCommand) {
user = input.getString();
doLogin(user);

} else if (c == okCommand) {
t = new SendThread(input.getString(),to.getString(),
msg.getString());

showAlert(t.getResponseMessage());
} else if (d == dmenu) {
handleMainMenu();
} else
loginUser();
}

private void displayMenu() {
dmenu = new List("Send Email", Choice.IMPLICIT);
if (user == null)
dmenu.append("Login", null);
else
dmenu.append("Logout", null);
dmenu.append("Send Mail", null);
dmenu.addCommand(exitCommand);
dmenu.setCommandListener(this);
display.setCurrent(dmenu);
status = 0;
}

/* Este m�todo pergunta ao usu�rio seu e-mail e sua senha */
private void loginUser() {
input = new TextBox(
"Digite Login/Password (Separado pela /) :", "", 25, 
TextField.ANY);

input.addCommand(submitCommand);
input.addCommand(backCommand);
input.setCommandListener(this);
display.setCurrent(input);
}

/* Este m�todo executa o inicio de uma sess�o */
private void doLogin(String user) {
StreamConnection c = null;
InputStream is=null;
StringBuffer sb = null;
String err = null;

try {
c = (StreamConnection)Connector.open(url, Connector.READ_WRITE);
is = c.openInputStream();
int ch;
sb = new StringBuffer();
while ((ch = is.read()) != -1) {
sb.append((char)ch);
}
} catch(Exception ex){ err = ex.getMessage(); } finally {
try {
if(is!= null) {is.close(); }
if(c != null) {c.close(); }
} catch(Exception exp) { err = exp.getMessage(); }
}
if (err == null) {
user = sb.toString();

if (user.indexOf("UsuarioInvalido") >= 0) {
user = null;
showAlert("Usuario e senha errados");
} else {
input = null;
dmenu = null;
displayMenu();
}
} else
showAlert(err); // Necess�rio para a p�gina de erro
}

private void showAlert(String err) {
Alert a = new Alert("");
a.setString(err);
a.setTimeout(Alert.FOREVER);
display.setCurrent(a);
}

private void handleMainMenu() {
int index = dmenu.getSelectedIndex();
switch(index) {
case 0 :
if (user != null) {
sendeMail();
break;
}
case 1 :
status = 1;
loginUser();
break;
}
}

/* Este m�todo permite que o usu�rio cria a mensagem do e-mail*/
private void sendeMail() {
List menu = new List("Enviar mensagem");
to = new TextBox("Para :", "", 50, TextField.ANY);
msg = new TextBox("Mensagem :", "", 250, TextField.ANY);
menu.append(to);
menu.append(msg);
menu.addCommand(okCommand);
menu.addCommand(exitCommand);
menu.setCommandListener(this);
display.setCurrent(menu);
}

public class SendThread implements runnable {
String user;
String pwd;
String to;
String msg;

public SendThread(String user,String to,String msg) {
int j user.indexOf('/');
if (j > 0) {
user = user.substring(0,j);
pwd = user.substring(j+1);
to = to;
msg = msg;
}
}

/*Este m�todo ob�tem a resposta depois do e-mail ser enviado*/
public String getResponseMessage() {
return responseMessage;
}

/* Este m�todo envia um POST request para o servlet com os par�mtros

 necess�rios*/
public void run() {
HttpConnection hc = null;
OutputStream out = null;
try {
hc = (HttpConnection)Connector.open(url);
hc.setRequestMethod(HttpConnection.POST);
hc.setRequestProperty("Content-Type", "text/plain");
out = hc.openOutputStream();
PrintStream pout = new PrintStream(out);
pout.println(user);
pout.println(pwd);
pout.println(mEmail);
pout.println(mMessage);

InputStream in = hc.openInputStream();
int length = (int)hc.getLength();
if (length == -1) length = 255;
byte[] raw = new byte[length];
in.read(raw);
String s = new String(raw);
String codeString = s.substring(0, 4).trim();
responseMessage = s.substring(4).trim();
} finally {
if (hc != null) hc.close();
if (out != null) out.close();
}
}
}
}

/*Servlet para enviar o e-mail*/
import java.io.*;
import java.text.*;
import java.util.*;
import javax.mail.*;
import javax.mail.internet.*;
import javax.servlet.http.*;
import javax.servlet.*;

public class SendMailServlet extends HttpServlet {
private String mMailServer;
private DateFormat mDateFormat;

public void init() {
mMailServer = "SeuServidor.com";
mDateFormat = new SimpleDateFormat("yyyy.MM.dd HH:mm:ss");
}

public void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, 
IOException {

BufferedReader in = request.getReader();
String user = in.readLine();
String pwd = in.readLine();
String address = in.readLine();

StringBuffer content = new StringBuffer();
String line = null;
while ((line = in.readLine()) != null) {
content.append(line);
content.append('\n');
}

String message = "100 ok";

try {
sendMail(mMailServer,user,pwd, address, content.toString());
} catch (Throwable t) {
message = "200 " + t.toString();
}
response.setContentType("text/plain");
response.setContentLength(message.length());
PrintWriter out = response.getWriter();
out.println(message);
out.flush();
}

/* Este m�todo cria a mensagem e envia para o servidor*/
private void sendMail(String server, String user, 
String pwd, String address, String content) throws Exception {

Properties p = new Properties();
p.put("mail.smtp.host", server);
Session s = Session.getDefaultInstance(p, null);
InternetAddress from = new InternetAddress(user);
InternetAddress to = new InternetAddress(address);
MimeMessage m = new MimeMessage(s);
m.setFrom(from);
m.addRecipient(Message.RecipientType.TO, to);
String now = mDateFormat.format(new java.util.Date());
m.setSubject("Mail from [" + from + "]");
m.setText(content.toString());
Transport.send(m);
}
 
}

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