import java.util.*;
import javax.servlet.*; 
import javax.servlet.http.*; 
import java.io.*;
import java.net.*;

public class JSendMail extends HttpServlet
        {
         PrintWriter outs;              //定義輸出對象
         static String PrintMailError;  //定義書寫郵件錯誤信息
         int isMailError,isSendMailError;
         String FromAddress,ToAddress,CCAddress,MailServerHost; //定義相關地址變量
         String EMailSubject,EmailText,MSubject_chs,MText_chs;  //定義郵件內容變量
         Vector CCAddressVector; //定義抄送地址對象
         int k;

         public void service(HttpServletRequest rq, HttpServletResponse rp)
           {
            /* 初始變量和對象*/
            JSendMail jsendmail = new JSendMail();
            PrintMailError = null;
            isMailError = 0;
            isSendMailError = 0;
            FromAddress = null;
            ToAddress = null;
            MailServerHost = null;
            CCAddress = null;
            EMailSubject = null;
            EmailText = null;
            MSubject_chs = null;
            MText_chs = null;
            rp.setContentType("text/html");

            try
              {
                /* 處理前臺的發送請求 */
                PrintWriter outs = rp.getWriter();
                FromAddress = rq.getParameter("txtfieldFrom");  //從前臺表單獲得變量值
                ToAddress = rq.getParameter("txtfieldTO");
                CCAddress = rq.getParameter("txtfieldCC");
                MailServerHost = rq.getParameter("txtfieldHost");
                EMailSubject = rq.getParameter("txtfieldSubject");
                EmailText = rq.getParameter("txtfieldText");
                MSubject_chs = new String(EMailSubject.getBytes("iso-8859-1")); //有效的處理中文字符集
                MText_chs = new String(EmailText.getBytes("iso-8859-1"));

                /* 檢查Email參數的正確性（合法性） */
                isMailError = jsendmail.checkMailError(FromAddress,ToAddress,CCAddress,MailServerHost,MSubject_chs,MText_chs);
                if (isMailError == 1)
                  {
                   /*
                    *  當isMailError=1時，表示郵件的參數存在錯誤的值。
                    *  將錯誤的參數名和錯誤原因反饋給客戶端。
                    */
                   outs.println(PrintMailError);
                  }
                else
                  {
                   /* 郵件參數正確，進行郵件的提交和轉發處理 */
                   try
                     {
                      isSendMailError = jsendmail.sendEMail(FromAddress,ToAddress,MailServerHost,MSubject_chs,MText_chs);
                      if (isSendMailError == 1)
                        {
                         /* 郵件發送完成 */
                         outs.println("<br><center><font size='6' color='#688eff' face='方正姚體'>你的郵件已經成功發送！</font></center>");
                        }
                      else
                        {
                         /* 郵件發送未完成 */
                         outs.println("<br><font size='5' color='#FF66CC' face='方正姚體'>你的郵件沒有被成功發送，其原因可能是你所填寫的收件人郵箱地址或Mail服務器地址有錯誤。請重新檢查一下所填寫的郵件地址，謝謝！</font>");
                        }
                     }
                   catch(Exception e)
                     {
                      /* 處理在郵件發送時遇到的例外 */
                      outs.println("<br><font size='5' color='#FF66CC' face='方正姚體'>你的郵件沒有被成功發送，其原因可能是你所填寫的收件人郵箱地址或Mail服務器地址有錯誤。請重新檢查一下所填寫的郵件地址，謝謝！</font>");
                     }
                   if (CCAddress != null && CCAddress.length() > 1)
                     {
                      try
                        {
                         /* 處理多個收信人的郵件轉發 */
                         CCAddressVector = new Vector(2,2);
                         CCAddressVector = jsendmail.cutCCMailAddress(CCAddress);

                         for(int j = 0;j < CCAddressVector.size();j++)
                           {
                            ToAddress = CCAddressVector.elementAt(j).toString().trim();
                            isSendMailError = jsendmail.sendEMail(FromAddress,ToAddress,MailServerHost,MSubject_chs,MText_chs);
                           }
                         if (isSendMailError == 1)
                           {
                            /* 郵件轉發完成 */
                            outs.println("<br><br><center><font size='6' color='#688eff' face='方正姚體'>你的郵件已經成功轉發！</font></center>");
                           }
                         else
                           {
                            /* 郵件轉發未完成 */
                            outs.println("<br><br><font size='5' color='#FF66CC' face='方正姚體'>你的郵件沒有被成功轉發，其原因可能是你所填寫的收件人郵箱地址或Mail服務器地址有錯誤。請重新檢查一下所填寫的郵件地址，謝謝！</font>");
                           }
                        }
                      catch(Exception e)
                        {
                         System.out.println("!1 程序出現了例外：" + e.toString());
                        }
                     }
                  }
              }
            catch (Exception e)
               {
                System.out.println("!2 程序出現了例外：" + e.toString());
               }
           }

         public int checkMailError(String cme_FromAddress,String cme_ToAddress,String cme_CCAddress,String cme_MailServerHost,String cme_MSubject_chs,String cme_MText_chs)
           {
            /* 這是一個檢驗Email參數完整性的方法（函數） */
            int i = 0;
            PrintMailError = "<center>系統發現你所提交的Email發送請求中含有以下的錯誤：</center>";

            if (cme_FromAddress == null || cme_FromAddress.length() < 1 || (cme_FromAddress.indexOf("@") == -1))
              {
               /* 參數不正確 */
               i = 1;
               PrintMailError = PrintMailError + "<br><center>（1） 發件人的郵箱地址為空或格式不正確；</center>";
              }
            if (cme_ToAddress == null || cme_ToAddress.length() < 1 || (cme_ToAddress.indexOf("@") == -1))
              {
               i = 1;
               PrintMailError = PrintMailError + "<br><center>（2） 收件人的郵箱地址為空或格式不正確；</center>";
              }

            if (cme_CCAddress != null && cme_CCAddress.length() > 1)
              {
               if (cme_CCAddress.indexOf("@") == -1)
                 {
                  i = 1;
                  PrintMailError = PrintMailError + "<br><center>（3） 抄送人的郵箱地址為空或格式不正確；</center>";
                 }
              }

            if (cme_MailServerHost == null || cme_MailServerHost.length() < 1 || (cme_MailServerHost.indexOf(".") == -1))
              {
               i = 1;
               PrintMailError = PrintMailError + "<br><center>（4） 郵件服務器的地址為空或格式不正確；</center>";
              }

            if ((cme_MSubject_chs == null || cme_MSubject_chs.length() < 1) && (cme_MText_chs == null || cme_MText_chs.length() < 1)) 
              {
               i = 1;
               PrintMailError = PrintMailError + "<br><center>（5） 郵件的主題和內容不可以同時為空；</center>";
              }

            return i;
           }

         public Vector cutCCMailAddress(String cma_CCAddress)
           {
            /* 這是一個獲取多個Email轉發地址的方法（函數） */
            Vector cutAddress = new Vector(2,2);
            StringTokenizer st = new StringTokenizer(cma_CCAddress,",");
            String v = null;
            int i = 0;
            int j = 0;
            int k = 0;

            for (i = 0;i < cma_CCAddress.length();i++)
              {
               /* 判斷轉發地址的個數 */
               j++;
               v = cma_CCAddress.substring(i,j);
               if(v.equals(","))
                 {
                  k++;
                 }
              }

            for(i = 0;i <= k;i++)
              {
               /* 以逗號為分隔符，將字符串分隔為若干個子字符串 */
               v = st.nextToken();
               if (v != null && v.length() > 1)
                 {
                  cutAddress.addElement(v.trim());
                 }
              }

            return cutAddress;
           }

         public int sendEMail(String sem_FromAddress,String sem_ToAddress,String sem_MailServerHost,String sem_MSubject_chs,String sem_MText_chs)
           {
            /* 這是一個發送郵件的方法（函數） */
            int i;

            try
              {
               Socket s = new Socket(sem_MailServerHost, 25);
               PrintStream out = new PrintStream(s.getOutputStream());
               BufferedReader in = new BufferedReader(new InputStreamReader(s.getInputStream()));
               out.println("HELO " + "aaa");
               in.readLine();
               out.println("MAIL FROM: " + sem_FromAddress);
               in.readLine();
               out.println("RCPT TO: " + sem_ToAddress);
               in.readLine();
               out.println("DATA");
               out.println("Subject:" + sem_MSubject_chs);
               out.println("\n");
               in.readLine();
               out.println(sem_MText_chs);
               in.readLine();
               out.println(".\n");
               in.readLine();
               out.println("QUIT");
               i = 1;
              }
            catch(Exception e)
              {
               i = 0;
               System.out.println("!3 程序出現了例外：" + e.toString());
              }

            return i;
           }
        }