Java连接到邮箱把邮件信息以及附件存放在数据库中

可以使用JavaMail API连接到邮箱，获取邮件信息和附件，然后使用JDBC将它们存储到数据库中。以下是一个简单的示例代码：

import java.sql.*;
import java.util.Properties;
import javax.mail.*;
import javax.mail.internet.*;

public class MailToDatabase {
    public static void main(String[] args) {
        String host = "imap.gmail.com";
        String username = "your_email@gmail.com";
        String password = "your_password";
        String databaseUrl = "jdbc:mysql://localhost:3306/mydatabase";
        String databaseUser = "root";
        String databasePassword = "root";

        Properties props = new Properties();
        props.setProperty("mail.store.protocol", "imaps");
        props.setProperty("mail.imaps.host", host);
        props.setProperty("mail.imaps.port", "993");

        try {
            Session session = Session.getInstance(props, null);
            Store store = session.getStore();
            store.connect(username, password);

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

            Message[] messages = inbox.getMessages();
            for (Message message : messages) {
                String subject = message.getSubject();
                String from = InternetAddress.toString(message.getFrom());
                String to = InternetAddress.toString(message.getRecipients(Message.RecipientType.TO));
                String cc = InternetAddress.toString(message.getRecipients(Message.RecipientType.CC));
                String bcc = InternetAddress.toString(message.getRecipients(Message.RecipientType.BCC));
                String sentDate = message.getSentDate().toString();
                String receivedDate = message.getReceivedDate().toString();
                String contentType = message.getContentType();

                // Save message metadata to database
                Connection conn = DriverManager.getConnection(databaseUrl, databaseUser, databasePassword);
                PreparedStatement stmt = conn.prepareStatement("INSERT INTO messages (subject, from, to, cc, bcc, sent_date, received_date, content_type) VALUES (?, ?, ?, ?, ?, ?, ?, ?)");
                stmt.setString(1, subject);
                stmt.setString(2, from);
                stmt.setString(3, to);
                stmt.setString(4, cc);
                stmt.setString(5, bcc);
                stmt.setString(6, sentDate);
                stmt.setString(7, receivedDate);
                stmt.setString(8, contentType);
                stmt.executeUpdate();
                stmt.close();
                conn.close();

                // Save message attachments to database
                Multipart multipart = (Multipart) message.getContent();
                for (int i = 0; i < multipart.getCount(); i++) {
                    BodyPart bodyPart = multipart.getBodyPart(i);
                    if (!Part.ATTACHMENT.equalsIgnoreCase(bodyPart.getDisposition()) &&
                            !StringUtils.isNotBlank(bodyPart.getFileName())) {
                        continue; // Skip non-attachment parts
                    }

                    // Save attachment to database
                    InputStream is = bodyPart.getInputStream();
                    conn = DriverManager.getConnection(databaseUrl, databaseUser, databasePassword);
                    stmt = conn.prepareStatement("INSERT INTO attachments (message_id, filename, content) VALUES (?, ?, ?)");
                    stmt.setInt(1, message.getMessageNumber());
                    stmt.setString(2, bodyPart.getFileName());
                    stmt.setBinaryStream(3, is, is.available());
                    stmt.executeUpdate();
                    stmt.close();
                    conn.close();
                }
            }

            inbox.close(false);
            store.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

请注意，此代码仅用于演示目的，实际应用中需要添加错误处理和安全性检查。