java - 如何在Java中设置Email客户端？

Question

我正在尝试用java编写非常简单的电子邮件客户端。 当我启动该程序时，我收到一条错误消息:

Exception in thread "main" javax.mail.AuthenticationFailedException: EOF on socket
        at com.sun.mail.pop3.POP3Store.protocolConnect(POP3Store.java:146)
        at javax.mail.Service.connect(Service.java:297)
        at javax.mail.Service.connect(Service.java:156)
        at SimpleEmailClient2.main(SimpleEmailClient2.java:21)
Java Result: 1

为什么？ 我使用 Gmail 帐户并启用 POP 和 IMAP 我的代码中可能存在什么错误？ 谢谢

这是代码:

import java.util.Properties;

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

public class SimpleEmailClient2 {

  public static void main(String[] args) throws Exception {

    Properties props = new Properties();

    String host = "pop.gmail.com";
    String provider = "pop3";

    Session session = Session.getDefaultInstance(props, new MailAuthenticator());
    Store store = session.getStore(provider);
    store.connect(host, null, null);

    Folder inbox = store.getFolder("INBOX");
    if (inbox == null) {
      System.out.println("No INBOX");
      System.exit(1);
    }
    inbox.open(Folder.READ_ONLY);

    Message[] messages = inbox.getMessages();
    for (int i = 0; i < messages.length; i++) {
      System.out.println("Message " + (i + 1));
      messages[i].writeTo(System.out);
    }
    inbox.close(false);
    store.close();
  }
}

class MailAuthenticator extends Authenticator {

  public MailAuthenticator() {
  }

  public PasswordAuthentication getPasswordAuthentication() {
    return new PasswordAuthentication("email@gmail.com", "password");
  }
}

Answer 1

我不相信 gmail 支持 pop3 提供商；你必须使用 pop3s 来代替。否则这应该可以正常工作。