sendmail.java

实现了发送电子邮件的功能

import java.io.*;
import java.awt.*;
import java.net.*;
class sendmail extends Frame
{
  PrintStream ps=null;
  DataInputStream dis=null;
  String strmailfrom,strmailto,strsubject,strbody;
  String strbodyend="\r\n. \r\n";
  TextArea taletter,tastatus;
  TextField tfmailfrom,tfmailto,tfsubject;
  Label Ibmailfrom,Ibmailto,Ibsubject,Ibletter,Ibstatus;
  Button btini,btsend;
  Socket smtp=null;
  public void send(String str) throws IOException
  {
    ps.println(str);
    ps.flush();
    tastatus.appendText("Java send:"+str+"\n");
  }
  public void receive() throws IOException
  {
    String readstr=dis.readLine();
    tastatus.appendText("Java receive:"+readstr+"\n");
  }
  public static void main(String args[])
  {
    sendmail sm=new sendmail();
    sm.show();
  }
  public sendmail()
  {
    setLayout(new FlowLayout());
    Ibmailfrom=new Label("从地址：");
    tfmailfrom=new TextField(" ",50);
    Ibmailto=new Label("发送到：");
    tfmailto=new TextField("  ",50);
    Ibsubject=new Label("标题：");
    tfsubject=new TextField(50);
    Ibletter=new Label("信件内容：");
    Ibstatus=new Label("发送邮件状态：");
    add(Ibmailfrom);
    add(tfmailfrom);
    add(Ibmailto);
    add(tfmailto);
    btsend=new Button("SEND!");
    btini=new Button("Initial");
    tastatus=new TextArea(8,50);
    tastatus.setEditable(false);
    taletter=new TextArea(10,50);
    add(Ibstatus);
    add(tastatus);
    add(btsend);
    add(btini);
    add(Ibsubject);
    add(tfsubject);
    setTitle("发电子邮件");
    resize(600,600);
   }
   public boolean action(Event evt,Object obj)
   {
     if(evt.target==btsend)
     {
        tastatus.appendText("Now Start to send.\n");
        try{
           String loc=InetAddress.getLocalHost().getHostName();
           send("HELO"+loc);
           receive();
           send("MAIL FROM:"+strmailfrom);
           receive(); 
           send("RECP TO:"+strmailto);
           receive();
           send("DATA");
           receive();
           send("SUBJECT"+strsubject);
           receive();
           send(strbody+strbodyend);
           receive();
           smtp.close();
        }catch(IOException e){tastatus.appendText("Error sending!\n");}
        tastatus.appendText("Send Complete!\n");
     }
     else if(evt.target==btini)
     {
        tastatus.appendText("Now Start to connet.\n");
        try{
           smtp=new Socket("center.njtu.edu.cn",25);
           OutputStream os=smtp.getOutputStream();
           ps=new PrintStream(os);
           InputStream is=smtp.getInputStream();
           dis=new DataInputStream(is);
           tastatus.appendText("Connet complete!\n");
         }catch(IOException e){tastatus.appendText("Error sending!\n");}
         strmailfrom=tfmailfrom.getText();
         strmailto=tfmailto.getText();
         strsubject=tfsubject.getText();
         strbody=taletter.getText();
     }
     return super.action(evt,obj); 
   }
   public boolean handleEvent(Event e)
   {
     if(e.id==Event.WINDOW_DESTROY){System.exit(0);}
     return super.handleEvent(e);
   }
}