Question

任何人都可以告诉我如何使用Java邮件向一群人发送邮件。我试过，但我在SendEmailToGroupDemo和start（）方法得到错误。感谢

package textfiles;
import java.util.ArrayList;

import java.util.List;

import java.util.Properties;

import java.util.Scanner;

import javax.mail.Address;

import javax.mail.Authenticator;

import javax.mail.Message;

import javax.mail.MessagingException;

import javax.mail.PasswordAuthentication;

import javax.mail.Session;

import javax.mail.Transport;

import javax.mail.internet.AddressException;

import javax.mail.internet.InternetAddress;

import javax.mail.internet.MimeMessage;

public class MailJava {


public static void main(String[] args) {

      // Create a SendEmail object and call start 
      // method to send a mail in Java.
      SendEmailToGroupDemo sendEmailToGroup = new SendEmailToGroupDemo();
      sendEmailToGroup.start();

     }

     private void start() {

      // For establishment of email client with 
      // Google's gmail use below properties.
      // For TLS Connection use below properties
      // Create a Properties object 
      Properties props = new Properties();

      // these properties are required
      // providing smtp auth property to true
      props.put("mail.smtp.auth", "true");
      // providing tls enability
      props.put("mail.smtp.starttls.enable", "true");
      // providing the smtp host i.e gmail.com
      props.put("mail.smtp.host", "smtp.gmail.com");
      // providing smtp port as 587
      props.put("mail.smtp.port", "587");

      // For SSL Connection use below properties

      /*props.put("mail.smtp.host", "smtp.gmail.com");
       props.put("mail.smtp.socketFactory.port", "465");
       props.put("mail.smtp.socketFactory.class",
         "javax.net.ssl.SSLSocketFactory");
       props.put("mail.smtp.auth", "true");
       props.put("mail.smtp.port", "465");*/

      // Create Scanner object to take necessary 
      // values from the user.
      Scanner scanner = new Scanner(System.in);

      System.out.println("Please provide your Username for Authentication ...");
      final String Username = scanner.next();

      System.out.println("Please provide your Password for Authentication ...");
      final String Password = scanner.next();

      System.out.println("Please provide Email Address from which you want to send Email ...");
      final String fromEmailAddress = scanner.next();

      System.out.println("Please provide Email Addresses to which you want to send Email ...");
      System.out.println("If you are done type : Done or done");

      // ArrayLists to store email addresses entered by user
      ArrayList< String> emails = (ArrayList< String >) getEmails();

      System.out.println("Please provide Subject for your Email ... ");
      final String subject = scanner.next();

      System.out.println("Please provide Text Message for your Email ... ");
      final String textMessage = scanner.next();

      // Create a Session object based on the properties and 
      // Authenticator object
      Session session = Session.getDefaultInstance(props, 
        new LoginAuthenticator(Username,Password));

      try {

       // Create a Message object using the session created above
       Message message = new MimeMessage(session);

       // setting email address to Message from where message is being sent
       message.setFrom(new InternetAddress(fromEmailAddress));

       // setting the email addressess to which user wants to send message 
       message.setRecipients(Message.RecipientType.BCC, getEmailsList(emails));

       // setting the subject for the email 
       message.setSubject(subject);

       // setting the text message which user wants to send to recipients
       message.setText(textMessage);

       // Using the Transport class send() method to send message 
       Transport.send(message);

       System.out.println("\nYour Message delivered successfully ....");

      } catch (MessagingException e) {

       throw new RuntimeException(e);

      }  
     }

     // This method takes a list of email addresses and 
     // returns back an array of Address by looping the 
     // list one by one and storing it into Address[]
     private Address[] getEmailsList(ArrayList< String > emails) {

      Address[] emaiAddresses = new Address[emails.size()];

      for (int i =0;i < emails.size();i++) {
       try {
        emaiAddresses[i] = new InternetAddress(emails.get(i));
       }
       catch (AddressException e) {

        e.printStackTrace();
       }
      }
      return emaiAddresses;
     }

     // This method prompts user for email group to which he
     // wants to send message
     public List< String > getEmails() {
      ArrayList< String > emails = new ArrayList< String >();

      int counter = 1;
      String address = "";
      Scanner scanner = new Scanner(System.in);

      // looping inifinitely times as long as user enters 
      // emails one by one
      // the while loop breaks when user types done and 
      // press enter.
      while(true) {

       System.out.println("Enter E-Mail : " + counter);
       address = scanner.next();

       if(address.equalsIgnoreCase("Done")){
        break;
       }
       else {
        emails.add(address);
        counter++;
       }
      }

      return emails;
     }
    }

    // Creating a class for Username and Password authentication
    // provided by the user.
    class LoginAuthenticator extends Authenticator {
     PasswordAuthentication authentication = null;

     public LoginAuthenticator(String username, String password) {
      authentication = new PasswordAuthentication(username,password);
     }

     @Override
     protected PasswordAuthentication getPasswordAuthentication() {
      return authentication;
     }
    }

Answer 1

替换它：

   // setting the email addressess to which user wants to send message 
   message.setRecipients(Message.RecipientType.BCC, getEmailsList(emails));

有了这个：

   // setting the email addressess to which user wants to send message
   for (String emailBcc : emails) {
       message.addRecipient(Message.RecipientType.BCC, new InternetAddress(emailBcc));
   }

之前我遇到过setRecipients（）问题，但从来没有使用addRecipient（）。

如果您遇到问题，我们将需要堆栈跟踪，并提供您所获得的确切错误/异常。

如何使用Javamail向一组人发送邮件

1 个答案: