编写java代码 从阿里云OSS下载指定目录下的所有文件

您好，以下是Java代码示例，可以从阿里云OSS下载指定目录下的所有文件：

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.model.ListObjectsRequest;
import com.aliyun.oss.model.ListObjectsResult;
import com.aliyun.oss.model.OSSObject;
import com.aliyun.oss.model.ObjectListing;

public class DownloadAllFilesFromOSS {

    public static void main(String[] args) {
        String endpoint = "yourEndpoint";
        String accessKeyId = "yourAccessKeyId";
        String accessKeySecret = "yourAccessKeySecret";
        String bucketName = "yourBucketName";
        String prefix = "yourPrefix"; // 指定目录

        OSS ossClient = new OSSClientBuilder().build(endpoint, accessKeyId, accessKeySecret);

        List<String> objectKeys = new ArrayList<String>();
        ObjectListing objectListing = null;

        do {
            ListObjectsRequest listObjectsRequest = new ListObjectsRequest(bucketName).withPrefix(prefix);
            if (objectListing != null) {
                listObjectsRequest.withMarker(objectListing.getNextMarker());
            }
            objectListing = ossClient.listObjects(listObjectsRequest);
            for (OSSObject ossObject : objectListing.getObjectSummaries()) {
                objectKeys.add(ossObject.getKey());
            }
        } while (objectListing.isTruncated());

        for (String objectKey : objectKeys) {
            try {
                OSSObject ossObject = ossClient.getObject(bucketName, objectKey);
                byte[] buffer = new byte[1024];
                int len;
                File file = new File(objectKey);
                File parentFile = file.getParentFile();
                if (!parentFile.exists()) {
                    parentFile.mkdirs();
                }
                FileOutputStream fos = new FileOutputStream(file);
                while ((len = ossObject.getObjectContent().read(buffer)) != -1) {
                    fos.write(buffer, 0, len);
                }
                fos.close();
                ossObject.getObjectContent().close();
            } catch (OSSException oe) {
                oe.printStackTrace();
            } catch (ClientException ce) {
                ce.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        ossClient.shutdown();
    }

}

请将代码中的 `yourEndpoint`、`yourAccessKeyId`、`yourAccessKeySecret`、`yourBucketName`、`yourPrefix` 替换为您自己的阿里云OSS信息。