Question

我需要开发一个连接到我的Gmail帐户的Java程序，对于每个邮件'x'，它应该system.out.println邮件的接收日期x。

我找到了关于javax.mail库的教程，但我不能system.out.println每封电子邮件的收到日期。

我使用了以下代码，但正如您可以看到下面的输出，它不会打印收到的日期：它只是打印字符串null。

你能帮我实现目标吗？

/*
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 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package Test;

import static java.lang.Math.log;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.Properties;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import javax.mail.Folder;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.NoSuchProviderException;
import javax.mail.Session;
import javax.mail.Store;
import javax.mail.internet.MimeMessage;


/**
 *
 * @author Andrea Caronello
 */
public class CheckingMails {

    public static final String RECEIVED_HEADER_DATE_FORMAT = "EEE, d MMM yyyy HH:mm:ss Z";
public static final String RECEIVED_HEADER_REGEXP = "^[^;]+;(.+)$";


     public static void check(String host, String storeType, String user,
      String password) 
   {
      try {

      //create properties field
      Properties properties = new Properties();

      properties.put("mail.pop3.host", host);
      properties.put("mail.pop3.port", "995");
      properties.put("mail.pop3.starttls.enable", "true");
      Session emailSession = Session.getDefaultInstance(properties);

      //create the POP3 store object and connect with the pop server
      Store store = emailSession.getStore("pop3s");

      store.connect(host, user, password);

      //create the folder object and open it
      Folder emailFolder = store.getFolder("INBOX");
      emailFolder.open(Folder.READ_ONLY);

      // retrieve the messages from the folder in an array and print it
      Message[] messages = emailFolder.getMessages();
      System.out.println("messages.length---" + messages.length);

      for (int i = 0, n = messages.length; i < n; i++) {
         Message message = messages[i];
         System.out.println("---------------------------------");
         System.out.println("Email Number " + (i + 1));
         System.out.println("Subject: " + message.getSubject());
         System.out.println("From: " + message.getFrom()[0]);
         System.out.println("Text: " + message.getContent().toString());
         System.out.println("ReceiveDate: " + message.getReceivedDate());


      }

      //close the store and folder objects
      emailFolder.close(false);
      store.close();

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

   public static void main(String[] args) {

      String host = "pop.gmail.com";// change accordingly
      String mailStoreType = "pop3";
      String username = "myGmailAccount@gmail.com";// change accordingly
      String password = "myPassword";// change accordingly

      check(host, mailStoreType, username, password);

}

   public Date resolveReceivedDate(MimeMessage message) throws MessagingException {
    if (message.getReceivedDate() != null) {
        return message.getReceivedDate();
    }
    String[] receivedHeaders = message.getHeader("Received");
    if (receivedHeaders == null) {
        return (Calendar.getInstance().getTime());
    }
    SimpleDateFormat sdf = new SimpleDateFormat(RECEIVED_HEADER_DATE_FORMAT);
    Date finalDate = Calendar.getInstance().getTime();
    finalDate.setTime(0l);
    boolean found = false;
    for (String receivedHeader : receivedHeaders) {
        Pattern pattern = Pattern.compile(RECEIVED_HEADER_REGEXP);
        Matcher matcher = pattern.matcher(receivedHeader);
        if (matcher.matches()) {
            String regexpMatch = matcher.group(1);
            if (regexpMatch != null) {
                regexpMatch = regexpMatch.trim();
                try {
                    Date parsedDate = sdf.parse(regexpMatch);
                    //LogMF.debug(log, "Parsed received date {0}", parsedDate);
                    if (parsedDate.after(finalDate)) {
                        //finding the first date mentioned in received header
                        finalDate = parsedDate;
                        found = true;
                    }
                } catch (Exception e) {
                    //LogMF.warn(log, "Unable to parse date string {0}", regexpMatch);
                }
            } else {
                //LogMF.warn(log, "Unable to match received date in header string {0}", receivedHeader);
            }
        }
    }

    return found ? finalDate : Calendar.getInstance().getTime();
}
}

--OUTPUT 
messages.length---4
---------------------------------
Email Number 1
Subject: Il meglio di Gmail, ovunque tu sia
From: Il team di Gmail <mail-noreply@google.com>
Text: javax.mail.internet.MimeMultipart@80b973
ReceiveDate: null
---------------------------------
Email Number 2
Subject: Tre suggerimenti per ottenere il massimo da Gmail
From: Il team di Gmail <mail-noreply@google.com>
Text: javax.mail.internet.MimeMultipart@10f3a9c
ReceiveDate: null
---------------------------------
Email Number 3
Subject: Organizza le tue email con la Posta in arrivo di Gmail
From: Il team di Gmail <mail-noreply@google.com>
Text: javax.mail.internet.MimeMultipart@d115db
ReceiveDate: null
---------------------------------
Email Number 4
Subject: test1
From: "maverick1984c@yahoo.com" <maverick1984c@yahoo.com>
Text: javax.mail.internet.MimeMultipart@f20964
ReceiveDate: null

Answer 1

您需要使用imap代替pop3。 POP3协议不支持收到日期。

另请注意，您使用pop3s调用了getStore，但设置了pop3的属性;这些名字必须匹配。在getStore中使用pop3然后将mail.pop3.ssl.enable设置为true会更简单。但同样，您需要将pop3替换为imap，以获取收到的日期。

最后，请务必修正其中任何common JavaMail mistakes。

如何使用Java阅读我的Gmail帐户的邮件接收日期？

1 个答案: