smtpclient.java

关于SMTP网络协议的实验 客户端程序

import java.io.IOException;
import java.io.*;
import java.net.Socket;
import java.net.SocketException;
import java.net.UnknownHostException;
import java.util.StringTokenizer;

import sun.misc.BASE64Encoder;

public class SMTPClient {

 private boolean debug=true;
 BASE64Encoder encode=new BASE64Encoder();//用于加密后发送用户名和密码
 public static void main(String[] args) throws UnknownHostException, IOException {
  // TODO Auto-generated method stub
  MailMessage message=new MailMessage();
  message.setFrom("[e-mail]");//发件人
  message.setTo("[e-mail]");//收件人
  String server="mail.bjtu.edu.cn";//邮件服务器
  message.setSubject("test");//邮件主题
  message.setContent("test");//邮件内容
  message.setDatafrom("[e-mail]");//发件人，在邮件的发件人栏目中显示
  message.setDatato("[e-mail]");//收件人，在邮件的收件人栏目中显示
  message.setUser("");//登陆邮箱的用户名
  message.setPassword("");//登陆邮箱的密码
  
  SMTPClient smtp=new SMTPClient(server,25);
  boolean flag;
  flag=smtp.sendMail(message,server);
  if(flag){
   System.out.println("邮件发送成功！");
  }
  else{
   System.out.println("邮件发送失败！");
  }

 }
 private Socket socket;
 public SMTPClient(String server,int port) throws UnknownHostException, IOException{
  try{
   socket=new Socket(server,25);
  }catch(SocketException e){
   System.out.println(e.getMessage());
  }catch(Exception e){
   e.printStackTrace();
  }finally{
   System.out.println("已经建立连接!");
  }

 }
 //注册到邮件服务器
 public void helo(String server,BufferedReader in,BufferedWriter out) throws IOException{
  int result;
  result=getResult(in);
  //连接上邮件服务后,服务器给出220应答
  if(result!=220){
   throw new IOException("连接服务器失败");
  }
  result=sendServer("HELO "+server,in,out);
  //HELO命令成功后返回250
  if(result!=250)
  {
   throw new IOException("注册邮件服务器失败！");
  }
 }
 
 private int sendServer(String str,BufferedReader in,BufferedWriter out) throws IOException{
  out.write(str);
  out.newLine();
  out.flush();
  if(debug)
  {
   System.out.println("已发送命令:"+str);
  }
  return getResult(in);
 }
 public int getResult(BufferedReader in){
  String line="";
  try{
   line=in.readLine();
   if(debug){
    System.out.println("服务器返回状态:"+line);
   }
  }catch(Exception e){
   e.printStackTrace();
  }
  //从服务器返回消息中读出状态码,将其转换成整数返回
  StringTokenizer st=new StringTokenizer(line," ");
  return Integer.parseInt(st.nextToken());
 }
 
 public void authLogin(MailMessage message,BufferedReader in,BufferedWriter out) throws IOException{
  int result;
  result=sendServer("AUTH LOGIN",in,out);
  if(result!=334){
   throw new IOException("用户验证失败！");
  }
  
   result=sendServer(encode.encode(message.getUser().getBytes()),in,out);
   if(result!=334){
   throw new IOException("用户名错误！"); 
   }
   result=sendServer(encode.encode(message.getPassword().getBytes()),in,out);
  
   if(result!=235){
    throw new IOException("验证失败！"); 
  }
 }
 //开始发送消息，邮件源地址
 public void mailfrom(String source,BufferedReader in,BufferedWriter out) throws IOException{
  int result;
  result=sendServer("MAIL FROM:<"+source+">",in,out);
  if(result!=250){
   throw new IOException("指定源地址错误");
  }
 }
 // 设置邮件收件人
 public void rcpt(String touchman,BufferedReader in,BufferedWriter out) throws IOException{
  int result;
  result=sendServer("RCPT TO:<"+touchman+">",in,out);
  if(result!=250){
   throw new IOException("指定目的地址错误！");
  }
 }
 
 //邮件体
 public void data(String from,String to,String subject,String content,BufferedReader in,BufferedWriter out) throws IOException{
  int result;
  result=sendServer("DATA",in,out);
  //输入DATA回车后,若收到354应答后,继续输入邮件内容
  if(result!=354){
   throw new IOException("不能发送数据");
  }
  out.write("From: "+from);
  out.newLine();
  out.write("To: "+to);
  out.newLine();
  out.write("Subject: "+subject);
  out.newLine();
  out.newLine();
  out.write(content);
  out.newLine();
  //句号加回车结束邮件内容输入
  result=sendServer(".",in,out);
  System.out.println(result);
  if(result!=250)
  {
   throw new IOException("发送数据错误");
  }
 }
 
 //退出
 public void quit(BufferedReader in,BufferedWriter out) throws IOException{
  int result;
  result=sendServer("QUIT",in,out);
  if(result!=221){
   throw new IOException("未能正确退出");
  }
 }
 
 //发送邮件主程序
 public boolean sendMail(MailMessage message,String server){
  try{
   BufferedReader in=new BufferedReader(new InputStreamReader(socket.getInputStream()));
   BufferedWriter out=new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));
   helo(server,in,out);//HELO命令
  // authLogin(message,in,out);//AUTH LOGIN命令
   mailfrom(message.getFrom(),in,out);//MAIL FROM
   rcpt(message.getTo(),in,out);//RCPT
   data(message.getDatafrom(),message.getDatato(),message.getSubject(),message.getContent(),in,out);//DATA
   quit(in,out);//QUIT
  }catch(Exception e){
   e.printStackTrace();
   return false;
   
  }
  return true;
 }

}