使用IMAP（javamail API）从gmail访问电子邮件

我正在尝试借助JavaMail API通过IMAP访问Gmail帐户中的电子邮件。 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。

我可以访问两个电子邮件帐户的Inbox文件夹。 但对于其中一个电子邮件帐户，无法访问其他文件夹，如SPAM([Gmail]/Spam) ，它会引发FolderNotFoundExceptionexception。 有人可以解释一下出了什么问题吗？

先谢谢你。

这是代码：

 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","[e-mail]", "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(); } } } } 

Answer 1

其中一个帐户是否有机会使用非英语用户界面？

Gmail文件夹名称已根据用户本地化设置进行了本地化。

目前获取本地化文件夹名称的唯一方法是使用XLIST命令。

Answer 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(); } } } 

Answer 3

我不确定这是否有帮助，但我已经看到gmail帐户有不同邮箱的情况，即..

Gmail帐户1： –

 [[Google Mail]] [[Google Mail]/All Mail] [[Google Mail]/Bin] [[Google Mail]/Drafts] [[Google Mail]/Important] [[Google Mail]/Sent Mail] [[Google Mail]/Spam] [[Google Mail]/Starred] 

Gmail帐户2： –

 [[Gmail]] [[Gmail]/All Mail] [[Gmail]/Bin] [[Gmail]/Drafts] [[Gmail]/Important] [[Gmail]/Sent Mail] [[Gmail]/Spam] [[Gmail]/Starred]