java - 如何使用Javamail仅检索40-50封电子邮件(例如Gmail)？

Question

我正在尝试使用javamail检索我的收件箱，我已经做到了，但是现在当我尝试加载代码时出现问题，它需要花费大量时间来阅读所有电子邮件，因为它读取了整个收件箱，但我只想要几封电子邮件应该获取最新的。

Properties properties = new Properties();
String host = "pop.gmail.com";// change accordingly
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, username, 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();
LOG.info("messages.length---" + messages.length);

for (int i = 0; i < messages.length; i++) {
    Message message = messages[i];
    leadJSONObject = new JSONObject();
    LOG.info("Email Number " + (i + 1));
    LOG.info("This log is executed successfully");
    leadJSONObject.put("emailFrom", message.getFrom()[0].toString());
    leadJSONObject.put("emailSubject", message.getSubject());
    leadJSONObject.put("emailText", message.getContent().toString());
    planJSONArray.put(leadJSONObject);
}

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

请帮助我如何只能阅读几封电子邮件。提前致谢。

Answer 1

您可能想要对消息进行计数，然后仅检索总数的一部分，例如前 50 条消息(如果不够的话则更少):

int total = emailFolder.getMessageCount();

Message[] messages =  emailFolder.getMessages(1,Math.min(total,50));

比照。 javax.mail.Folder 的 javadoc .