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我需要开发一个连接到我的gmail帐户和每个邮件'x'的Java程序，它应该接收邮件x的日期。如何阅读使用Java的Gmail帐户的邮件接收日期？
我在javax.mail库上找到了一个教程，但是我不能在每个电子邮件的接收日期为system.out.println。
我使用了下面的代码，但是您可以看到下面的输出，它不打印接收日期：它只是打印字符串null。
你能帮我实现我的目标吗？
/*
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* 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 = "[email protected]";// 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 <[email protected]>
Text: [email protected]
ReceiveDate: null
---------------------------------
Email Number 2
Subject: Tre suggerimenti per ottenere il massimo da Gmail
From: Il team di Gmail <[email protected]>
Text: [email protected]
ReceiveDate: null
---------------------------------
Email Number 3
Subject: Organizza le tue email con la Posta in arrivo di Gmail
From: Il team di Gmail <[email protected]>
Text: [email protected]
ReceiveDate: null
---------------------------------
Email Number 4
Subject: test1
From: "[email protected]" <[email protected]>
Text: [email protected]
ReceiveDate: null