Chapter One Introduction to Java Network programming _mailclient.java

Import java.net.*;
Import java.io.*;

public class mailsender{
Private String smtpserver= "smtp.mydomain.com"; The host name of the SMTP mail server
Private String smtpserver= "localhost";
private int port=25;

public static void main (string[] Args) {
Message msg=new message ("[email protected]",//sender's email address
"[email Protected]",//recipient's Email Address
"hello",//mail Header
"hi,i Miss you very much."); Message body
New MailSender (). SendMail (msg);
}

public void SendMail (Message Msg) {
Socket socket=null;
try{
Socket = new Socket (smtpserver,port); Connect to a mail server
BufferedReader BR =getreader (socket);
PrintWriter pw = Getwriter (socket);
String localhost= inetaddress.getlocalhost (). gethostname (); The name of the Client's host

SendAndReceive (null,br,pw); Just to receive the Server's response data
SendAndReceive ("HELO" + localhost,br,pw);
SendAndReceive ("MAIL from: <" + msg.from+ ">", br,pw);
SendAndReceive ("RCPT to: <" + msg.to+ ">", br,pw);
SendAndReceive ("DATA", br,pw); Next start sending message content
Pw.println (msg.data); Send Message Content
System.out.println ("client>" +msg.data);
SendAndReceive (".", br,pw); Message sent
SendAndReceive ("QUIT", br,pw); End Communication
}catch (ioexception E) {
E.printstacktrace ();
}finally{
try{
If (socket!=null) socket.close ();
}catch (ioexception E) {e.printstacktrace ();}
}
}

/** sends a row of strings and receives response data for a row of servers */
private void SendAndReceive (String Str,bufferedreader br,printwriter Pw) throws ioexception{
If (str! = Null) {
System.out.println ("client>" +str);
Pw.println (str); After sending the STR string, "\ r \ n" is also sent.
}
String response;
If ((response = br.readline ()) = Null)
System.out.println ("server>" +response);
}

Private PrintWriter getwriter (socket Socket) throws ioexception{
OutputStream socketout = Socket.getoutputstream ();
return new PrintWriter (socketout,true);
}
Private BufferedReader Getreader (socket Socket) throws ioexception{
InputStream Socketin = Socket.getinputstream ();
return new BufferedReader (new InputStreamReader (socketin));
}
}

Class Message{//indicates Mail
String from; Sender's E-mail Address
String to; Recipient's Email Address
String subject; Message header
String content; Message body
String data; Message content, including message headers and body text
Public Message (string from,string to, string subject, string Content) {
this.from=from;
this.to=to;
this.subject=subject;
this.content=content;
Data= "Subject:" +subject+ "\ r \ n" +content;
}
}

Authmailclient.java

Import java.net.*;
Import java.io.*;

public class mailsenderwithauth{
Private String smtpserver= "smtp.163.com"; The host name of the SMTP mail server
private int port=25;

public static void main (string[] Args) {
Message msg=new message ("[email protected]",//sender's email address
"[email Protected]",//recipient's Email Address
"hello",//mail Header
"hi,i Miss you very much."); Message body
New Mailsenderwithauth (). SendMail (msg);
}

public void SendMail (Message Msg) {
Socket socket=null;
try{
Socket = new Socket (smtpserver,port); Connect to a mail server
BufferedReader BR =getreader (socket);
PrintWriter pw = Getwriter (socket);
String localhost= inetaddress.getlocalhost (). gethostname (); The name of the Client's host

String username= "[email protected]";
String password= "38633638sa";
Base64 encoding of user names and passwords
Username = new Sun.misc.BASE64Encoder (). encode (username.getbytes ());
Password = new Sun.misc.BASE64Encoder (). encode (password.getbytes ());
SendAndReceive (null,br,pw); Just to receive the Server's response data
SendAndReceive ("EHLO" + localhost,br,pw);
SendAndReceive ("AUTH LOGIN", br,pw); Authentication command
SendAndReceive (username,br,pw); User name
SendAndReceive (password,br,pw); Password
SendAndReceive ("MAIL from:" + msg.from+ "", br,pw);

SendAndReceive ("RCPT to:" + msg.to+ "", br,pw);
SendAndReceive ("DATA", br,pw); Next start sending message content
Pw.println (msg.data); Send Message Content
System.out.println ("client>" +msg.data);
SendAndReceive (".", br,pw); Message sent
SendAndReceive ("QUIT", br,pw); End Communication
}catch (ioexception E) {
E.printstacktrace ();
}finally{
try{
If (socket!=null) socket.close ();
}catch (ioexception E) {e.printstacktrace ();}
}
}

/** sends a row of strings and receives response data for a row of servers */
private void SendAndReceive (String Str,bufferedreader br,printwriter Pw) throws ioexception{
If (str! = Null) {
System.out.println ("client>" +str);
Pw.println (str); After sending the STR string, "\ r \ n" is also sent.
}
String response;
If ((response = br.readline ()) = Null)
System.out.println ("server>" +response);
}

Private PrintWriter getwriter (socket Socket) throws ioexception{
OutputStream socketout = Socket.getoutputstream ();
return new PrintWriter (socketout,true);
}
Private BufferedReader Getreader (socket Socket) throws ioexception{
InputStream Socketin = Socket.getinputstream ();
return new BufferedReader (new InputStreamReader (socketin));
}
}

Class Message{//indicates Mail
String from; Sender's E-mail Address
String to; Recipient's Email Address
String subject; Message header
String content; Message body
String data; Message content, including message headers and body text
Public Message (string from,string to, string subject, string Content) {
this.from=from;
this.to=to;
this.subject=subject;
this.content=content;
Data= "Subject:" +subject+ "\ r \ n" +content;
}
}

Chapter One Introduction to Java Network programming _mailclient.java