使用IMAP（javamail API）访问来自gmail的电子邮件

java gmail imap jakarta-mail

2022-09-01 17:40:02

我正在尝试在JavaMail API的帮助下通过IMAP访问来自Gmail帐户的电子邮件。我想知道为什么代码适用于一个电子邮件帐户，但不适用于另一个电子邮件帐户。

我能够访问两个电子邮件帐户的文件夹。但是对于其中一个电子邮件帐户，无法访问其他文件夹（如其他文件夹），并且会引发异常。任何人都可以解释一下出了什么问题吗？InboxSPAM([Gmail]/Spam)FolderNotFoundException

提前感谢您。

代码如下：

import java.io.*;
import java.util.*;
import javax.mail.*;
import javax.mail.Flags.Flag;
import javax.mail.internet.*;

import com.sun.mail.imap.IMAPFolder;
import com.sun.mail.imap.IMAPMessage;


public class FolderFetchIMAP {


    public static void main(String[] args) throws MessagingException, IOException {
        IMAPFolder folder = null;
        Store store = null;
        String subject = null;
        Flag flag = null;
        try 
        {
          Properties props = System.getProperties();
          props.setProperty("mail.store.protocol", "imaps");

          Session session = Session.getDefaultInstance(props, null);

          store = session.getStore("imaps");
          store.connect("imap.googlemail.com","myemailid@gmail.com", "password");

          folder = (IMAPFolder) store.getFolder("[Gmail]/Spam"); // This doesn't work for other email account
          //folder = (IMAPFolder) store.getFolder("inbox"); This works for both email account


          if(!folder.isOpen())
          folder.open(Folder.READ_WRITE);
          Message[] messages = folder.getMessages();
          System.out.println("No of Messages : " + folder.getMessageCount());
          System.out.println("No of Unread Messages : " + folder.getUnreadMessageCount());
          System.out.println(messages.length);
          for (int i=0; i < messages.length;i++) 
          {

            System.out.println("*****************************************************************************");
            System.out.println("MESSAGE " + (i + 1) + ":");
            Message msg =  messages[i];
            //System.out.println(msg.getMessageNumber());
            //Object String;
            //System.out.println(folder.getUID(msg)

            subject = msg.getSubject();

            System.out.println("Subject: " + subject);
            System.out.println("From: " + msg.getFrom()[0]);
           System.out.println("To: "+msg.getAllRecipients()[0]);
            System.out.println("Date: "+msg.getReceivedDate());
            System.out.println("Size: "+msg.getSize());
            System.out.println(msg.getFlags());
            System.out.println("Body: \n"+ msg.getContent());
            System.out.println(msg.getContentType());

          }
        }
        finally 
        {
          if (folder != null && folder.isOpen()) { folder.close(true); }
          if (store != null) { store.close(); }
        }

    }



}

答案 1

其中一个帐户是否有机会使用非英语UI？

Gmail 文件夹名称会根据用户本地化设置进行本地化。

目前，获取本地化文件夹名称的唯一方法是使用 XLIST 命令。

答案 2

package com.technicalkeeda;

import java.io.File;
import java.io.FileInputStream;
import java.util.Properties;

import javax.mail.Folder;
import javax.mail.Message;
import javax.mail.Session;
import javax.mail.Store;

public class GmailInbox {

 public static void main(String[] args) {
  GmailInbox gmail = new GmailInbox();
  gmail.read();
 }

 public void read() {
  Properties props = new Properties();
  try {
   props.load(new FileInputStream(new File("C:\\smtp.properties")));
   Session session = Session.getDefaultInstance(props, null);

   Store store = session.getStore("imaps");
   store.connect("smtp.gmail.com", "*************@gmail.com","your_password");

   Folder inbox = store.getFolder("inbox");
   inbox.open(Folder.READ_ONLY);
   int messageCount = inbox.getMessageCount();

   System.out.println("Total Messages:- " + messageCount);

   Message[] messages = inbox.getMessages();
   System.out.println("------------------------------");
   for (int i = 0; i < 10; i++) {
      System.out.println("Mail Subject:- " + messages[i].getSubject());      
   }
   inbox.close(true);
   store.close();

  } catch (Exception e) {
   e.printStackTrace();
  }
 }

}