List<File> attachments = Collections.singletonList(new File("C:\\images\\test.jpg"));

Long messageId = mailSendService.sendMultiMail(
        mailList, getLoginUserId(), UserTypeEnum.ADMIN.getValue(),
        templateCode, templateParams, attachments);

import java.io.*;
import java.net.URL;
import java.nio.file.Files;
import java.nio.file.StandardCopyOption;

public class FileDownloadUtil {
    public static File downloadFileFromUrl(String fileUrl) throws IOException {
        URL url = new URL(fileUrl); // 創(chuàng)建 URL 對(duì)象
        File tempFile = File.createTempFile("attachment_", ".jpg"); // 生成臨時(shí)文件
        try (InputStream in = url.openStream()) {
            Files.copy(in, tempFile.toPath(), StandardCopyOption.REPLACE_EXISTING);
        }
        return tempFile;
    }
}

// 處理附件，將 HTTP 圖片下載到本地
List<File> attachments = new ArrayList<>();
try {
    File downloadedFile = FileDownloadUtil.downloadFileFromUrl(cabinetSwapDO.getImgCntrF());
    attachments.add(downloadedFile);
} catch (IOException e) {
    e.printStackTrace(); // 記錄日志
}

// 發(fā)送郵件
Long xx = mailSendService.sendMultiMail(mail, getLoginUserId(), UserTypeEnum.ADMIN.getValue(),
        templateCode, templateParams, attachments);

import javax.activation.DataHandler;
import javax.activation.URLDataSource;
import javax.mail.internet.MimeBodyPart;
import java.net.URL;

public class MailAttachmentUtil {
    public static MimeBodyPart createUrlAttachment(String fileUrl) throws Exception {
        MimeBodyPart attachmentPart = new MimeBodyPart();
        URL url = new URL(fileUrl);
        attachmentPart.setDataHandler(new DataHandler(new URLDataSource(url)));
        attachmentPart.setFileName("attachment.jpg"); // 可根據(jù)實(shí)際情況動(dòng)態(tài)命名
        return attachmentPart;
    }
}

public static File downloadFileFromUrl(String fileUrl, String saveDir) throws IOException {
    URL url = new URL(fileUrl);
    
    // 確保目錄存在
    File directory = new File(saveDir);
    if (!directory.exists()) {
        directory.mkdirs();
    }

    // 指定下載文件路徑
    File file = new File(saveDir + File.separator + "attachment.jpg");
    
    // 下載文件
    try (InputStream in = url.openStream()) {
        Files.copy(in, file.toPath(), StandardCopyOption.REPLACE_EXISTING);
    }

    return file;
}

File file = downloadFileFromUrl("http://example.com/image.jpg", "D:\\attachments");
System.out.println("Saved file path: " + file.getAbsolutePath());