[JAVA100 example]046, receiving messages using the SMTP protocol

Import java.io.*;


import java.net.*;


/**


* <P>TITLE:SMTP protocol receive mail </p>


* <p>description: Connect POP3 server via socket, use SMTP protocol to receive mail </p>
in mail server

* <p>copyright:copyright (c) 2003</p>


* <p>filename: </p>


* @version 1.0


*/


class Pop3demo


{


/**


*<br> Method Description: Main method, receive user input


*<br> input Parameters:


*<br> return type:


*/


public static void Main (string[] args) {


if (args.length!=3) {


System.out.println ("Use:java pop3demo mailhost user password");


　 }


new Pop3demo (). Receive (args[0],args[1],args[2]);


　}


/**


*<br> Method Description: Receive mail


*<br> input parameter: String popserver server Address


*<br> input parameter: String popuser mailbox User name


*<br> input parameter: String Poppassword mailbox Password


*<br> return type:


*/


public static void receive (String popserver, String popuser, string Poppassword)


　{


String pop3server = popserver;


int pop3port = 110;


Socket client = null;


Try


　 {


//Create a socket that is connected to the POP3 service program.


client = new Socket (Pop3server, Pop3port);


//Creates a BufferedReader object to read the output from the socket.


InputStream is = Client.getinputstream ();


BufferedReader Sockin;


Sockin = new BufferedReader (new InputStreamReader (IS));


//Creates a PrintWriter object to write content to the socket.


outputstream OS = Client.getoutputstream ();


PrintWriter sockout;


Sockout = new PrintWriter (OS, true); True for Auto-flush


//Display POP3 handshake information.


System.out.println ("S:" + sockin.readline ());





/*--handshake process with POP3 server--*/


System.out.print ("C:");


String cmd = "user" +popuser;


//Send user name to POP3 service program.


System.out.println (CMD);


sockout.println (CMD);


//Read the POP3 Service program's response message.


String reply = Sockin.readline ();


System.out.println ("S:" + Reply);


System.out.print ("C:");


cmd = "pass";


//Send the password to the POP3 service program.


System.out.println (cmd+ "*********");


sockout.println (Cmd+poppassword);


//Read the POP3 Service program's response message.


reply = Sockin.readline ();


System.out.println ("S:" + Reply);





　　　　


System.out.print ("C:");


cmd = "stat";


//Get mail data.


System.out.println (CMD);


sockout.println (CMD);


//Read the POP3 Service program's response message.


reply = Sockin.readline ();


System.out.println ("S:" + Reply);


if (reply==null) return;


System.out.print ("C:");


cmd = "Retr 1";


//will receive the first abundance mail commands to the POP3 service program.


System.out.println (CMD);


sockout.println (CMD);





//entered the RETR command and returned a successful response code, continuously reading the output from the socket,


//until you meet <CRLF>.<CRLF>. The output that is read from the socket is the content of the message.


if (Cmd.tolowercase (). StartsWith ("RETR") &&


Reply.charat (0) ==´+´)


do


　　　　{


reply = Sockin.readline ();


System.out.println ("S:" + Reply);


if (reply!= null && reply.length () > 0)


if (Reply.charat (0) ==´.´)


break;


　　　　}


while (true);


cmd = "quit";


//sends the command to the POP3 service program.


System.out.print (CMD);


sockout.println (CMD);


　 }


catch (IOException e)


　 {


System.out.println (e.tostring ());


　 }


finally


　 {


Try


{if (client!= null)


Client.close ();


　　 }


catch (IOException e)


　　 {


　　 }


　 }


　}


}