java - 使用 Java Mail API 从 Gmail 导出所有电子邮件

Question

所以我正在尝试编写一个程序，从我的电子邮件地址抓取所有电子邮件并将它们保存到文本文件中，我遇到的问题是使用 Java Mail API 抓取多于 1 封电子邮件。

这是我用来获取电子邮件的方法，效果很好，但我想获取收件箱中的每封电子邮件:

    public static void checkMail(String username, String password) {
    Properties props = new Properties();
    props.setProperty("mail.store.protocol", "imaps");
    try {
        Session session = Session.getInstance(props, null);
        Store store = session.getStore();
        store.connect("imap.gmail.com", username, password);
        Folder inbox = store.getFolder("INBOX");
        inbox.open(Folder.READ_ONLY);
        Message msg = inbox.getMessage(inbox.getMessageCount());
        Address[] in = msg.getFrom();
        for (Address address : in) {
            System.out.println("FROM:" + address.toString());
        }
        Multipart mp = (Multipart) msg.getContent();
        BodyPart bp = mp.getBodyPart(0);
        System.out.println("SENT DATE:" + msg.getSentDate());
        System.out.println("SUBJECT:" + msg.getSubject());
        System.out.println("CONTENT:" + bp.getContent());
    } catch (Exception mex) {
        mex.printStackTrace();
    }
}

如果有人可以向我展示如何执行此操作或解释它，那么我将不胜感激。

Answer 1

如果您想要文件夹收件箱中的所有邮件，请执行以下操作:

public static void checkMail(String username, String password) {
    Properties props = new Properties();
    props.setProperty("mail.store.protocol", "imaps");
    try {
        Session session = Session.getInstance(props, null);
        Store store = session.getStore();
        store.connect("imap.gmail.com", username, password);
        Folder inbox = store.getFolder("INBOX");
        inbox.open(Folder.READ_ONLY);
        Message[] msgs = inbox.getMessages();

        for (Message msg : msgs) {
            try {
                Address[] in = msg.getFrom();
                for (Address address : in) {
                    System.out.println("FROM:" + address.toString());
                }
                Multipart mp = (Multipart) msg.getContent();
                BodyPart bp = mp.getBodyPart(0);
                System.out.println("SENT DATE:" + msg.getSentDate());
                System.out.println("SUBJECT:" + msg.getSubject());
                System.out.println("CONTENT:" + bp.getContent());
            } catch (Exception e) {

                e.printStackTrace();
            }
        }
        // close folder and store (normally in a finally block)
        inbox.close(false);
        store.close();

    } catch (Exception mex) {
        mex.printStackTrace();
    }
}

如果您想要从其他文件夹发送邮件，则必须对所有文件夹执行相同的操作。您可以使用 store.getDefaultFolder().list() 获取它们(对所有文件夹递归执行此操作，因为文件夹可以包含子文件夹)

protected void recurseFolders(final Folder folder) {
    // folder can hold messages
    if ((folder.getType() & Folder.HOLDS_MESSAGES) != 0) {

        // process them

    }

    // folder can hold other folders
    if ((folder.getType() & Folder.HOLDS_FOLDERS) != 0) {
        for (final Folder subfolder : folder.list()) {

            // process them recursive
            recurseFolders(subfolder);

        }
    }

}

看这里:https://github.com/salyh/elasticsearch-river-imap