通過163smtp服務器向各大郵箱發送郵件(SOCKET編程)

package server;

import java.io.*;
import java.net.*;
import java.sql.Time;
import java.util.Scanner;
import java.util.Timer;

public class client {
    
    /*通過163smtp服務器向其他郵箱發送數據
     * 返回碼
     * 0：未知原因出錯
     * 1：發送成功
     * 2：被判定為垃圾郵件
    */
    public static int send(Mail mail){
        int state=0;
        Socket socket=null;
        String userName="xxxxxxxxx";//經過base64編碼的163郵箱用戶名
        String password="xxxxxxxxxxxxxx";//經過base64編碼的163郵箱密碼
        BufferedReader reader=null;
        PrintWriter writer=null;
        try {
            // 連接到服務器
            socket = new Socket("SMTP.163.com", 25);
            reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            writer = new PrintWriter(socket.getOutputStream(), true);
            System.out.println(reader.readLine());
            writer.println("HELO 163");
            System.out.println(reader.readLine());
            writer.println("auth login");   
            System.out.println(reader.readLine());   
            writer.println(userName);   
            System.out.println(reader.readLine());   
            writer.println(password);   
            System.out.println(reader.readLine()); 
            writer.println("mail from:<[e-mail]>");
            System.out.println(reader.readLine());   
            writer.println("rcpt to:<" +mail.getReceiver()+">");   
            System.out.println(reader.readLine()); 
            //開始發送郵件
            writer.println("data");
            System.out.println(reader.readLine());
            writer.println("subject:"+mail.getSubject());
            writer.println("from:"+mail.getSender());
            writer.println("to:"+mail.getReceiver());
            writer.println("Content-Type: text/plain;charset=\"gb2312\"");   
            writer.println("");   
            writer.println(mail.getContent());   
            writer.println(".");   
            writer.println("");   
            String sum=reader.readLine();
            System.out.println(sum);
            if(sum.indexOf("250")==0){
                System.out.println("發送成功");
                state=1;
            }else if(sum.indexOf("554")==0){
                System.out.println("被判定為垃圾郵件");
                state=2;
            }
            writer.println("rset");   
            System.out.println(reader.readLine());   
            writer.println("quit");   
        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            try {
                socket.close();
                reader.close();
                writer.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        return state;
    }
    
    public static void main(String[] args){
        Mail mail=new Mail("[e-mail]","[e-mail]","你好","吃飯了沒");
        System.out.println(send(mail));
        
    }
}

注意如果是163向163發送郵件，郵件的發送者（mail.sender,不是真實發送者這個必須和認證的用戶名相同)可以設置為任意的，這樣接收者收到郵件時會看到該郵件由認證的用戶代發

但是如果是163向其他郵箱發送郵件，這兩個from必須相同，否則大部分情況下都會被163當作是垃圾郵件返回554錯誤，無發發送