Javamail 性能

I've been using javamail to retrieve mails from IMAP server (currently GMail). Javamail retrieves list of messages (only ids) in a particular folder from server very fast, but when I actually fetch message (only envelop not even contents) it takes around 1 to 2 seconds for each message. What are the techniques should be used for fast retrieval?

这是我的代码:

    try {
        IMAPStore store = null;
        if(store!=null&&store.isConnected())return;
        Properties props = System.getProperties();
        Session sessionIMAP = Session.getInstance(props, null);
        try {
            store = (IMAPStore) sessionIMAP.getStore("imaps");
            store.connect("imap.gmail.com",993,"username@gmail.com","password");
        } catch (Exception e) {
            e.printStackTrace();
        }

        IMAPFolder folder = (IMAPFolder) store.getFolder("INBOX");
        folder.open(Folder.READ_ONLY);
        System.out.println("start");
        Message[] msgs = folder.getMessages(1,10);
        long ftime = System.currentTimeMillis();
        FetchProfile fp=new FetchProfile();
        fp.add(FetchProfile.Item.ENVELOPE);
        folder.fetch(msgs, fp);
        long time = System.currentTimeMillis();
        System.out.println("fetch: "+(time-ftime));
        for (Message message : msgs) {
            System.out.println(message.getSubject());
            Address[] from = message.getFrom();
            for (Address address : from) {
                System.out.println(address);
            }
            Address[] recipients = message.getAllRecipients();
            for (Address address : recipients) {
                System.out.println(address);
            }

        }
        long newTime = System.currentTimeMillis();
        System.out.println("convert: "+(newTime-time));
    }catch (Exception e) {
        e.printStackTrace();
    }


}

推荐答案

我相信 Gmail 会将 IMAP 消息的读取限制为每秒一次左右.您或许可以通过多个 IMAP 连接来加快速度.