当java中已经存在邮件时，如何跳过复制收件箱文件夹中的邮件？

Properties properties = new Properties();
properties.setProperty("mail.store.protocol", "imap"); // 使用IMAP协议
properties.setProperty("mail.imap.host", "邮件服务器地址");
properties.setProperty("mail.imap.port", "邮件服务器端口");

Session session = Session.getDefaultInstance(properties);
Store store = session.getStore("imap");
store.connect("邮箱账号", "邮箱密码");

Folder inbox = store.getFolder("INBOX");
inbox.open(Folder.READ_WRITE); // 打开收件箱文件夹

Message[] messages = inbox.getMessages();
for (Message message : messages) {
    // 处理每个邮件
}

Flags flags = message.getFlags();
if (!flags.contains(Flags.Flag.SEEN)) {
    // 未读邮件，进行复制操作
}

message.setFlag(Flags.Flag.SEEN, true);

import javax.mail.*;
import java.util.Properties;

public class SkipCopyEmails {
    public static void main(String[] args) throws Exception {
        Properties properties = new Properties();
        properties.setProperty("mail.store.protocol", "imap");
        properties.setProperty("mail.imap.host", "邮件服务器地址");
        properties.setProperty("mail.imap.port", "邮件服务器端口");

        Session session = Session.getDefaultInstance(properties);
        Store store = session.getStore("imap");
        store.connect("邮箱账号", "邮箱密码");

        Folder inbox = store.getFolder("INBOX");
        inbox.open(Folder.READ_WRITE);

        Message[] messages = inbox.getMessages();
        for (Message message : messages) {
            Flags flags = message.getFlags();
            if (!flags.contains(Flags.Flag.SEEN)) {
                // 复制邮件操作

                // 将邮件标记为已读
                message.setFlag(Flags.Flag.SEEN, true);
            }
        }

        inbox.close(false);
        store.close();
    }
}