如何使用java从gcp bucket下载文件夹？

import com.google.auth.oauth2.GoogleCredentials;
import com.google.cloud.storage.Blob;
import com.google.cloud.storage.BlobId;
import com.google.cloud.storage.Storage;
import com.google.cloud.storage.StorageOptions;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;

public class GCPBucketDownloader {
    public static void main(String[] args) {
        String bucketName = "your-bucket-name";
        String folderName = "your-folder-name";
        String destinationPath = "your-destination-path";

        try {
            // 从凭据文件创建GoogleCredentials对象
            GoogleCredentials credentials = GoogleCredentials.fromStream(
                    GCPBucketDownloader.class.getResourceAsStream("/path/to/credentials.json")
            );

            // 使用GoogleCredentials对象创建Storage实例
            Storage storage = StorageOptions.newBuilder().setCredentials(credentials).build().getService();

            // 列出文件夹中的所有Blob对象
            Iterable<Blob> blobs = storage.list(bucketName, Storage.BlobListOption.prefix(folderName)).iterateAll();

            // 遍历Blob对象并下载到本地
            for (Blob blob : blobs) {
                String blobName = blob.getName();
                String filePath = destinationPath + File.separator + blobName;

                // 创建本地文件
                File file = new File(filePath);
                file.getParentFile().mkdirs();
                file.createNewFile();

                // 下载Blob到本地文件
                try (FileOutputStream fos = new FileOutputStream(file)) {
                    fos.write(blob.getContent());
                }
            }

            System.out.println("文件夹下载完成！");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}