When you retrieve mail, you connect to a server that supports the Post Office Protocol, Version 3 (POP3) or Internet Message Access Protocol, Version 4 (IMAP4) protocol.Implement Email Client on device and interact with POP3/IMAP4 server through HTTP protocol, using servlet.
/*Midlet running on device*/
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 CheckMail extends MIDlet implements CommandListener {
private String MAIL_SERVER_URL =
"http://localhost:8080/examples/servlet/CheckMailServlet?";
private int MSG_LIST_SIZE = 5;
Display display = null;
List menu = null;
List dmenu = null;
TextBox input = null;
String[] msgs = new String[MSG_LIST_SIZE];
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);
public CheckMail() { }
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) {
handleBack();
} else if (c == submitCommand) {
user = input.getString();
retreiveMail(0, null);
} else if (d == dmenu) {
handleMainMenu();
} else if (d == menu) {
handleMsgMenu();
} else
loginUser();
}
/* Display Main Screen */
private void displayMenu() {
dmenu = new List("Check Email", Choice.IMPLICIT);
if (user == null)
dmenu.append("Login", null);
else
dmenu.append("Logout", null);
dmenu.append("Check Mail", null);
dmenu.addCommand(exitCommand);
dmenu.setCommandListener(this);
display.setCurrent(dmenu);
status = 0;
}
/* This method takes users Mail ID and password*/
private void loginUser() {
input = new TextBox(
"Enter Login Name/Password (Seperate by /) :", "", 25,
TextField.ANY);
input.addCommand(submitCommand);
input.addCommand(backCommand);
input.setCommandListener(this);
display.setCurrent(input);
}
/* This method retrieves Message with msgNum and
if no MsgNum, displays the list of all msgs*/
private void retreiveMail(int s, String msgNum) {
String popURL = MAIL_SERVER_URL + "u=" + user;
if (s == 0)
popURL = popURL // Login
if (s == 1)
// List messages
popURL = popURL + "&s=" + msgNum + "&a=l";
else if (s == 2)
// Retreive message with i = msgNum
popURL = popURL + "&i=" + msgNum + "&a=r";
StreamConnection c = null;
InputStream is=null;
StringBuffer sb = null;
String err = null;
try {
c = (StreamConnection)Connector.open(popURL,
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) {
if (s == 0) {
user = sb.toString();
if (user.indexOf("INVALIDUSR") >= 0) {
user = null;
showAlert("Invalid User Name and Password");
} else {
input = null;
dmenu = null;
displayMenu();
}
} else if (s == 1) // For retreiving the list
showMList(sb.toString());
else // s ==2, show Message
showMsg(sb.toString());
} else
showAlert(err); // Need to Show Error Page
}
/* Display the selected Message*/
private void showMsg(String msg) {
StringBuffer buffer = new StringBuffer(200);
int delim = 'ß';
int j = msg.indexOf(delim);
int i =0;
// Get's FROM
buffer.append(msg.substring(0,j ));
for (int k=0;k<4;k++) {
i = j+1;
j = msg.indexOf(delim, i);
// Get's TO, CC, Subject, Date
buffer.append(msg.substring(i,j ));
}
// Rest of the Message
buffer.append("\n" + msg.substring(j+1 ));
showAlert(buffer.toString());
}
/* Display Error On screen*/
private void showAlert(String err) {
Alert a = new Alert("");
a.setString(err);
a.setTimeout(Alert.FOREVER);
display.setCurrent(a);
}
/* Display MessageList of User*/
private void showMList(String msgStr) {
for (int i=0;i<MAX_LIST_SIZE;i++) {
msgs = "";
}
menu = new List("Messages", Choice.IMPLICIT);
int delim = 'ß';
String sub = null;
int i =0;
int k = 0;
int l =0;
int j =msgStr.indexOf(delim);
while( j >= 0) {
sub = msgStr.substring(i,j);
if ((k % 2) == 0) {
msgs[l] = sub; // First would be Message Number
l++;
} else
menu.append(sub, null);
k++;
i = j + 1;
j = msgStr.indexOf(delim, i); // Rest of substrings
}
sub = msgStr.substring(i); // Last substring
menu.append(sub, null);
menu.addCommand(backCommand);
menu.addCommand(exitCommand);
menu.setCommandListener(this);
status = 1;
display.setCurrent(menu);
}
private void handleBack() {
if (status == 1) {
dmenu = null;
displayMenu();
} else
display.setCurrent(menu);
}
private void handleMainMenu() {
int index = dmenu.getSelectedIndex();
switch(index) {
case 0 :
if (user != null) {
retreiveMail(1, "0");
break;
}
case 1 :
status = 1;
loginUser();
break;
case 2 :
break;
}
}
private void handleMsgMenu() {
int index = menu.getSelectedIndex();
if (!msgs[index].equals("")) {
retreiveMail(2, msgs[index]); // Retreive Mail
}
}
}
/*Servlet communicating with Mail server*/
import java.io.*;
import java.util.StringTokenizer;
import java.util.Vector;
import javax.mail.*;
import javax.mail.internet.MimeMessage;
import javax.servlet.*;
import javax.servlet.http.*;
public class CheckMailServlet extends HttpServlet {
private static String MSG_NOMAIL = "NOMAIL";
private static String MSG_INVALID_USER = "INVALIDUSR";
private static String MSG_CRITCAL_ERR = "UNEXPECTEDERROR";
public CheckMailServlet() {
String hostname = "yourserver.com"
// Get system properties
Properties props = System.getProperties();
props.put("mail.pop3.host", "hostname");
Session session = Session.getDefaultInstance(props, null);
Store store = session.getStore("pop3");
}
/*Get the request parameters */
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws IOException {
try {
String action = request.getParameter("a");
if(action == null)
doLogin(request, response);
else if(action.equals("r")) //retrieve
doRetrieve(request, response);
else if(action.equals("l")) //List
doList(request, response);
} catch(Exception e) {
PrintWriter writer = response.getWriter();
writer.println(MSG_CRITCAL_ERR);
writer.flush();
}
}
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws IOException {
doGet(request, response);
}
/* performs login for user and returns status*/
private void doLogin(HttpServletRequest request,
HttpServletResponse response) throws ServletException,
IOException, MessagingException {
String uid = request.getParameter("u");
String pwd, tmpUID;
String responeStr = null;
if ((uid == null) || (uid.equals("")) ) {
responeStr = MSG_INVALID_USER;
} else {
int j =uid.indexOf('/');
if (j > 0) {
tmpUID = uid.substring(0,j);
pwd = uid.substring(j+1);
if(login(tmpUID,pwd)) {
responeStr = tmpUID;
flag = true;
} else
responeStr = MSG_INVALID_USER;
} else
responeStr = MSG_INVALID_USER;
}
PrintWriter writer = response.getWriter();
writer.print(responeStr);
writer.flush();
}
public boolean login(String uid, String pwd) // login
{
store.connect(hostname,uid,pwd);
if (store.isConnected()) {
return true;
} else
return false;
}
/* List all messages from Inbox*/
private void doList(HttpServletRequest request,
HttpServletResponse response) throws ServletException,
IOException, MessagingException {
String uid = request.getParameter("u");
String responeStr = "";
MailLister lister = null;
StringBuffer buffer = new StringBuffer(200);
try {
lister = getMailLister(uid);
} catch(Exception exp) {
throw new ServletException(exp.getMessage());
}
if ( (lister != null) && (lister.size() > 0)) {
Vector vect = lister.keys();
int listSize = vect.size();
int endingNum = (listSize > 8) ? (listSize - 8) : 0;
for (int j = listSize-1; j>=endingNum; j--) {
String curKey = (String)vect.elementAt(j);
String msgString = (String)lister.get(curKey);
if (j != endingNum)
buffer.append( curKey + "ß" + msgString + "ß");
else
buffer.append(curKey + "ß" + msgString);
}
responeStr = buffer.toString();
} else
responeStr = MSG_NOMAIL;
PrintWriter writer = response.getWriter();
writer.print(responeStr);
writer.flush();
}
/* Stores all messages in Hashtable */
private MailLister getMailLister(String uid) throws Exception {
MailLister lister = null;
int j =uid.indexOf('/');
String ud;
String pwd;
if (j > 0) {
ud = uid.substring(0,j);
pwd = uid.substring(j+1);
if(login(ud,pwd)) {
// Open the Folder
Folder folder = store.getDefaultFolder();
if (folder == null) {
System.out.println("No default folder");
return null;
}
folder = folder.getFolder("INBOX");
if (folder == null) {
System.out.println("Invalid folder");
return null;
}
folder.open(Folder.READ_ONLY);
// Get directory
Message message[] = folder.getMessages();
lister = new MailLister()
for (int i=0, n=message.length; i<n; i++) {
Message m = folder.getMessage(i);
lister.put(m,i);
}
} else
return lister;
} else
return lister;
return lister;
}
/* Retrieve Selected Mail from Inbox with msgID*/
private void doRetrieve(HttpServletRequest request,
HttpServletResponse response) throws ServletException,
IOException, MessagingException {
String msgId = request.getParameter("i");
String uid = request.getParameter("u");
try {
Message msg = getMessageFromStore(msgId, uid);
if (msg == null)
throw new ServletException(
"Could not Load the Message File");
writeMessage(msg, request, response, uid, msgId);
} catch(Exception exp) {
throw new ServletException(exp.getMessage());
}
}
private String getMsgHeading(Message msg) throws Exception {
StringBuffer buffer = new StringBuffer(300);
buffer.append("From:");
getAddressesList(msg.getFrom(), buffer);
buffer.append(" To:");
getAddressesList(
msg.getRecipients(javax.mail.Message.RecipientType.TO),
buffer);
buffer.append(" Subject:");
buffer.append(msg.getSubject());
buffer.append(" Date:");
buffer.append(msg.getSentDate());
return buffer.toString();
}
/* This method gives the name and email of person*/
private void getAddressesList(Address addresses[], StringBuffer buffer)
throws Exception {
String uName;
String uEmail;
if(addresses != null) {
for(int i = 0; i < addresses.length; i++) {
buffer.append(addresses + ";");
}
}
}
/* write Message according to MIME type and send to mobile screen*/
protected void writeMessage(Message msg, HttpServletRequest request,
HttpServletResponse response, String uid, String msgId)
throws Exception {
if(msg.isMimeType("multipart/*")) {
Multipart multipart = (Multipart)msg.getContent();
int msgPartCount = multipart.getCount();
StringBuffer buffer = new StringBuffer(200);
for(int i = 0; i < msgPartCount; i++) {
Part p = multipart.getBodyPart(i);
if (i == 0) {
buffer.append(getMsgHeading(msg));
}
if(p.isMimeType("text/plain")) {
String content = (String)p.getContent();
buffer.append(content.trim());
} else {
String filename = p.getFileName();
buffer.append(" --- Has attachement " + filename);
}
if (i == (msgPartCount-1)) {
response.setContentType("text/plain");
PrintWriter writer = null;
writer = response.getWriter();
writer.print(removeExtraChar(buffer.toString(), '\n'));
writer.flush();
}
}
} else if(msg.isMimeType("text/plain")) {
printAscii(response, (String)msg.getContent() , msg);
} else // For HTML or another type of Content
{
writePart(msg, -1, response);
}
}
private void printAscii(HttpServletResponse response,
String currentText, Message msg ) throws Exception {
PrintWriter writer = response.getWriter();
if (currentText.length() > 1500)
currentText = currentText.substring(0,1500);
writer.print(getMsgHeading(msg) + currentText);
writer.flush();
}
private Message getMessageFromStore(String msgUID, String uid)
throws Exception {
MailLister lister = getMailLister(uid)
if(lister != null) {
return lister.get(msgUID);
} else
return null;
}
private void writePart(Message msg, int partnr,
HttpServletResponse response) throws Exception {
Part p = msg;
String responseStr;
if (p.isMimeType("text/html")) {
String str = (String)p.getContent();
if (str.length() > 1500)
str = str.substring(0,1500);
responseStr = removeHTMLFormatting(str);
responseStr = removeExtraChar(responseStr, '\n');
} else
responseStr = "The MIME Type in which this mail exist is not"+
" supported on J2ME Phone";
response.setContentType("text/plain");
PrintWriter writer = response.getWriter();
writer.print(getMsgHeading(msg) + responseStr);
writer.flush();
}
private String removeHTMLFormatting(String str) {
boolean insideTag = false;
String token;
StringBuffer buffer = new StringBuffer(200);
StringTokenizer st = new StringTokenizer( str , "<>", true);
while( st.hasMoreTokens() ) {
token = st.nextToken();
if ( token.equals( "<" ) )
insideTag = true;
else if ( token.equals( ">" ) )
insideTag = false;
else if ( insideTag == false )
buffer.append( token );
}
return buffer.toString();
}
private String removeExtraChar(String str, int delim) {
StringBuffer buffer = new StringBuffer(200);
// First substring
int j =str.indexOf(delim);
int i = 0;
while( j >= 0) {
// Add some extra space
buffer.append(" " + str.substring(i,j));
i = j + 1;
j = str.indexOf(delim, i); // Rest of substrings
}
buffer.append(str.substring(i)); // Last substring
return buffer.toString();
}
/* This class stores all messages in Hashtable and retrieves them
according to given key*/
public class MailLister implements java.io.Serializable {
private Hashtable hash;
private Vector vect;
public MailLister() {
vect = new Vector();
hash = new Hashtable(vect.capacity());
}
public Object get(Object obj) {
return hash.get(obj);
}
public void put(Object key, Object val) {
if(!vect.contains(key))
vect.insertElementAt(key, vect.size());
hash.put(key, val);
}
}
}