imap java代码,JAVA运用IMAP、POP3、SMTP协议收发邮件

以下是使用Java Mail API实现IMAP、POP3、SMTP协议收发邮件的示例代码：

1. IMAP收取邮件

import java.util.Properties;
import javax.mail.Folder;
import javax.mail.Message;
import javax.mail.Session;
import javax.mail.Store;

public class IMAPMailReceiver {
    public static void main(String[] args) throws Exception {
        String host = "imap.host.com";
        String user = "user@host.com";
        String password = "password";

        Properties props = new Properties();
        props.setProperty("mail.store.protocol", "imap");
        props.setProperty("mail.imap.host", host);
        props.setProperty("mail.imap.port", "993");
        props.setProperty("mail.imap.socketFactory.class", "javax.net.ssl.SSLSocketFactory");

        Session session = Session.getInstance(props);
        Store store = session.getStore();
        store.connect(user, password);

        Folder inboxFolder = store.getFolder("INBOX");
        inboxFolder.open(Folder.READ_ONLY);

        Message[] messages = inboxFolder.getMessages();
        for (Message message : messages) {
            System.out.println("Subject: " + message.getSubject());
            System.out.println("From: " + message.getFrom()[0]);
            System.out.println("Sent Date: " + message.getSentDate());
            System.out.println("Message: " + message.getContent().toString());
        }

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

2. POP3收取邮件

import java.util.Properties;
import javax.mail.Folder;
import javax.mail.Message;
import javax.mail.Session;
import javax.mail.Store;

public class POP3MailReceiver {
    public static void main(String[] args) throws Exception {
        String host = "pop3.host.com";
        String user = "user@host.com";
        String password = "password";

        Properties props = new Properties();
        props.setProperty("mail.store.protocol", "pop3");
        props.setProperty("mail.pop3.host", host);
        props.setProperty("mail.pop3.port", "995");
        props.setProperty("mail.pop3.socketFactory.class", "javax.net.ssl.SSLSocketFactory");

        Session session = Session.getInstance(props);
        Store store = session.getStore();
        store.connect(user, password);

        Folder inboxFolder = store.getFolder("INBOX");
        inboxFolder.open(Folder.READ_ONLY);

        Message[] messages = inboxFolder.getMessages();
        for (Message message : messages) {
            System.out.println("Subject: " + message.getSubject());
            System.out.println("From: " + message.getFrom()[0]);
            System.out.println("Sent Date: " + message.getSentDate());
            System.out.println("Message: " + message.getContent().toString());
        }

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

3. SMTP发送邮件

import java.util.Properties;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;

public class SMTPMailSender {
    public static void main(String[] args) throws Exception {
        String host = "smtp.host.com";
        String user = "user@host.com";
        String password = "password";

        Properties props = new Properties();
        props.put("mail.smtp.host", host);
        props.put("mail.smtp.port", "587");
        props.put("mail.smtp.auth", "true");
        props.put("mail.smtp.starttls.enable", "true");

        Session session = Session.getDefaultInstance(props);
        MimeMessage message = new MimeMessage(session);
        message.setFrom(new InternetAddress(user));
        message.setRecipient(Message.RecipientType.TO, new InternetAddress("recipient@host.com"));
        message.setSubject("Test Email");
        message.setText("This is a test email");

        Transport transport = session.getTransport("smtp");
        transport.connect(host, user, password);
        transport.sendMessage(message, message.getAllRecipients());
        transport.close();
    }
}

以上示例代码仅供参考，实际使用时需要根据实际情况进行调整。