使用javax.mail發送大量電子郵件，某些電子郵件的發送失敗

Question

我向使用javax.mail的用戶發送大量電子郵件（大約1000個），這些用戶來自我的SMTP服務器，該郵件擁有我的域名。所有的收件人都在同一個域名的電子郵件。

發送郵件時，如果只有成功，那麼我將令牌保存在userToken表中。否則，我不會將該令牌保存在表中。該過程完成後，userToken表將插入950行，這意味着所有電子郵件都會成功。

我已經寫了下面的代碼發送批量電子郵件，但幾乎300個電子郵件沒有收到用戶。我din't得到執行時的錯誤，

@RequestMapping(value = "bulkMail") 
public @ResponseBody String bulkMail(Model model, HttpServletRequest request,@RequestParam(value="myArray") Long[] myArray, HttpServletResponse response) throws IOException { 
    Session session = null; 
    EntityManagerFactory entityManagerFactory = Persistence.createEntityManagerFactory("roca"); 
    EntityManager entityManager = entityManagerFactory.createEntityManager(); 
    entityManager.getTransaction().begin(); 
    HttpSession httpSession = request.getSession(false); 
    session = getRocaSession(); 
    Test test = (Test) httpSession.getAttribute("test"); 

    for (int i = 0; i < myArray.length; i++) { 
     User user = entityManager.createQuery("SELECT u FROM User u where u.userId=" + myArray[i], User.class).getSingleResult(); 

     UserToken userToken; 
     try { 
      userToken = entityManager.createQuery("SELECT ut FROM UserToken ut where ut.testId="+test.getId()+" and ut.userId="+myArray[i], UserToken.class).getSingleResult(); 
     } catch (Exception e) { 
      userToken = new UserToken(); 
     } 

     String mailStatus = sendMail(userToken,test,request, user.getUserId(), user.getUserName(), context, user.getEmailId(),session); 
     if (!mailStatus.equals("failure")) { 
      userToken.setToken(mailStatus); 
      userToken.setCreatedDate(new Date()); 
      userToken.setUpdatedDate(new Date()); 
      userToken.setTestId(test.getId()); 
      userToken.setUserId(user.getUserId()); 
      userToken.setUsed(0); 
      testDao.saveOrUpdate(userToken); 
     } 
    } 
    entityManager.getTransaction().commit(); 
    entityManager.close(); 
    return "Emails have been send to Users"; 
} 

發送電子郵件

public String sendMail(UserTestToken userTestToken, Test test,HttpServletRequest request, Long accountId,String accountName, 
     String context,String accountEmail,Session session) { 
    String token = getToken(); 
    try { 
     String email = mailService.sendAlert(test, accountEmail,"User Triger", "noreply@mydomain.com", "Val", accountId, token, context, accountName, session); 
     if (!email.equals("failure")) { 
      return token; 
     }else { 
      return "failure"; 
     } 
    } catch (Exception e) { 
     return "failure"; 
    }  
} 

獲取會話的電子郵件

public Session getSession() { 
    Properties props = new Properties(); 
    props.put("mail.smtp.auth", "false"); 
    props.put("mail.smtp.host", "gatesmtp.moc.domain.com"); 
    props.put("mail.smtp.port", "25"); 
    Session session = Session.getInstance(props); 
    session.setDebug(false); 
    return session; 
} 

MailService的Implementaion

public String sendTestMailAlert(Test test, String accountEmail, String receiverName, String senderEmail, String url, Long accountId, String token, String context, String  accountName, Session session) 
{ 
    String subject = "Subject"; 
    String content = "Content"; 
    return sendMail(accountEmail, content, subject, receiverName, senderEmail, session); 
} 


private String sendMail(String receiverMailIds, String content, String subject, String employeeName, String employeeEmail, Session session) { 
    try { 
     Message message = new MimeMessage(session); 
     try { 
      message.setFrom(new InternetAddress(employeeEmail, employeeName)); 
     } catch (UnsupportedEncodingException e) { 
      this.logger.error("Mail service address catch UnsupportedEncodingException"); 
     } 
     message.setRecipients(Message.RecipientType.TO, InternetAddress.parse(receiverMailIds)); 
     message.setSubject(subject); 
     message.setContent(content, "text/html"); 
     Transport.send(message); 
     return "success"; 
    } catch (Exception e) { 
     this.logger.error("Mail Exception - " + receiverMailIds); 
    } 
    return "failure"; 
} 

Answer 1

問題不在你的代碼中：if郵件在郵件服務器中正確排隊，問題出現在最終收件人的SMTP服務器上。

當您的SMTP服務器（必須正確傳遞郵件入隊）聯繫收件人SMTP服務器，可能（當然...）收件人SMTP拒絕電子郵件出於某種原因（垃圾郵件？未知用戶？太多郵件？郵箱已滿？） 。因此，您的SMTP服務器無法傳送電子郵件，並嘗試將其發送回發件人（您定義爲「noreply@domain.com」）。如果此郵箱不存在，您的SMTP服務器將刪除郵件，並且（通常）僅在其內部日誌中記錄該操作。這就是爲什麼你不能注意到發生了什麼。

您可以用於測試目的而不是正確的發件人地址。

玩得開心:)