如何使用连接池为多个用户重用 java 邮件 API 中的 store.connect()

Question

我已经使用连接池来重用store.connect()。它对单个用户有效，但对多个用户无效。

对于多个用户，它为所有其他用户获取第一个加载的用户数据。 如何解决这个问题。

下面是代码，

public class EmailListingController {

    private static EmailListingController instance = null;
    private static Store store = null;

    public EmailListingController() {
        super();
    }

    private EmailListingController(String host, String mailstoreType, String username, String originalPassword,
            int port, boolean auth, boolean security, User user) throws MessagingException {
        System.out.println("props + store connect");
        Properties properties = new Properties();
        properties.put("mail.store.protocol", mailstoreType);
        properties.put("mail.imaps.host", host);
        properties.put("mail.imaps.port", port);
        properties.put("mail.smtp.ssl.enable", security);
        Session session = Session.getInstance(properties);
        store = session.getStore();
        store.connect(username, originalPassword);
    }

    public static synchronized EmailListingController getInstance(String host, String mailstoreType, String username,
            String originalPassword, int port, boolean auth, boolean security, User user) throws MessagingException {
        System.out.println("instance");
        if (instance == null) {
            instance = new EmailListingController(host, mailstoreType, username, originalPassword, port, auth, security,
                    user);
        }
        return instance;
    }

    @GetMapping("/inbox/{userId}")
    public ResponseEntity test(@PathVariable("userId") Integer id) {
        Optional<User> user = userService.findById(id);
        List<Email> emailList = new ArrayList<Email>();
        if (user.isPresent()) {
            String username = user.get().getUserName();
            String pwd = user.get().getPassword();

            EmailListingController client = EmailListingController.getInstance(host, mailstoreType, username,
                    pwd, port, auth, security, user.get());
            Folder folder = store.getFolder("inbox");
            folder.open(Folder.READ_ONLY);
            String from;String subject;String message1;String cc;String to;String bcc;
            String[] toArray = null;String[] ccArray = null;String[] bccArray = null;Email email2;
            FetchProfile fp1 = new FetchProfile();
            fp1.add(FetchProfile.Item.ENVELOPE);
            fp1.add(IMAPFolder.FetchProfileItem.FLAGS);
            fp1.add(IMAPFolder.FetchProfileItem.CONTENT_INFO);
            fp1.add(UIDFolder.FetchProfileItem.UID);
            folder.fetch(folder.getMessages(), fp1);
            for (Message message : folder.getMessages()) {
                System.out.println("message" + message.getSubject());
            }
            return new ResponseEntity(emailList, HttpStatus.OK);
        }
    }
}

任何帮助将不胜感激！