Question

我有一个包含GUI的应用程序，它使用的是Javamail。当我打开此Jframe时，我必须在jTextArea上看到发送到我邮件的邮件。

问题在于，当我编写代码时，它只显示最后发送的消息。

如何在收件箱中显示所有新讯息？

这是我的代码：

private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {

Properties props = new Properties();

props.put("mail.pop3.host", "pop.gmail.com");

props.put("mail.pop3.user", "mymail@gmail.com");

props.put("mail.pop3.socketFactory", 995);

props.put("mail.pop3.socketFactory.class", "javax.net.ssl.SSLSocketFactory");

props.put("mail.pop3.port", 995);

Session session = Session.getDefaultInstance(props, new Authenticator() {
    @Override
    protected PasswordAuthentication getPasswordAuthentication() {
        return new PasswordAuthentication("mymail@gmail.com", "mypassword");

    }
});

try {
    Store store = session.getStore("pop3");

    store.connect("pop.gmail.com", "mymail@gmail.com", "mypaswword");

    Folder fldr = store.getFolder("INBOX");

    fldr.open(Folder.READ_ONLY);

    Message[] msg = fldr.getMessages();

    Address[] address;


    for (int i = 0; i < msg.length; i++) {

        jTextArea1.setText("SentDate : " + msg[i].getSentDate() + "\n" + "From : " + msg[i].getFrom()[0] + "\n" + "Subject : " + msg[i].getSubject() + "\n" + "Message : " + "\n" + msg[i].getContent().toString());

    }

    fldr.close(true);

    store.close();

} catch (Exception e) {
    System.out.println(e);
}

Answer 1

您在此处重复将jTextArea1的文本设置为循环中的相同内容：

for (int i = 0; i < msg.length; i++) {

    jTextArea1.setText("SentDate : " + msg[i].getSentDate() + "\n" + "From : " + msg[i].getFrom()[0] + "\n" + "Subject : " + msg[i].getSubject() + "\n" + "Message : " + "\n" + msg[i].getContent().toString());

}

您应该使用所有消息构建StringBuilder，然后设置jTextArea1

的内容

final StringBuilder sb = new StringBuilder();
for (int i = 0; i < msg.length; i++) {

    sb.append("SentDate : " + msg[i].getSentDate() + "\n" + "From : " + msg[i].getFrom()[0] + "\n" + "Subject : " + msg[i].getSubject() + "\n" + "Message : " + "\n" + msg[i].getContent().toString());

}
jTextArea1.setText(sb.toString());

然后，您可以使用增强的for循环并使用append的{{1}}方法，使其更加清晰。

StringBuilder

Answer 2

final StringBuilder sb = new StringBuilder();
for (Message message : msg) {

    sb.append("SentDate : ").
        append(message.getSentDate()).
        append("\n").
        append("From : ").
        append(message.getFrom()[0]).
        append("\n").append("Subject : ").
        append(message.getSubject()).
        append("\n").
        append("Message : ").
        append("\n").
        append(message.getContent().toString());

}
jTextArea1.setText(sb.toString());

使用javamail从我的Gmail中读取所有新消息

2 个答案: