S3Java-使用预先指定的URL进行多部分上载？

我有一个单独的服务来管理文件和s3身份验证。它生成预先签名的URL，我可以在其他服务中使用这些URL上载（和下载）文件

我想利用Multipart upload sdk——目前“uploadToUrl”方法似乎将大部分时间花在getResponseCode上，因此很难提供用户反馈。而且，在我的测试中，多部分上传似乎要快得多

理想情况下，我希望能够使用预先指定的URL创建一些AWSCredentials，而不是临时使用的密钥/访问密钥。那只是白日梦吗

//s3 service
public URL getUrl(String bucketName, String objectKey, Date expiration, AmazonS3 s3Client, HttpMethod method, String contentType) {
    GeneratePresignedUrlRequest generatePresignedUrlRequest;

    generatePresignedUrlRequest = new GeneratePresignedUrlRequest(bucketName, objectKey);
    generatePresignedUrlRequest.setMethod(method);
    generatePresignedUrlRequest.setExpiration(expiration);
    generatePresignedUrlRequest.setContentType(contentType);

    URL s = s3Client.generatePresignedUrl(generatePresignedUrlRequest);
    System.out.println(String.format("Generated Presigned URL: %n %S", s.toString()));
    return s;
}

//Upload service
Override
public void uploadToUrl(URL url, File file) {

    HttpURLConnection connection;
    try {
        InputStream inputStream = new FileInputStream(file);
        connection = (HttpURLConnection) url.openConnection();
        connection.setDoOutput(true);
        connection.setRequestMethod("PUT");
        OutputStream out =
                connection.getOutputStream();

        byte[] buf = new byte[1024];
        int count;
        int total = 0;
        long fileSize = file.length();

        while ((count =inputStream.read(buf)) != -1)
        {
            if (Thread.interrupted())
            {
                throw new InterruptedException();
            }
            out.write(buf, 0, count);
            total += count;
            int pctComplete = new Double(new Double(total) / new Double(fileSize) * 100).intValue();

            System.out.print("\r");
            System.out.print(String.format("PCT Complete: %d", pctComplete));
        }
        System.out.println();
        out.close();
        inputStream.close();

        System.out.println("Finishing...");
        int responseCode = connection.getResponseCode();

        if (responseCode == 200) {
            System.out.printf("Successfully uploaded.");
        }
    } catch (IOException e) {
        e.printStackTrace();
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
}

---

目前，我正在探索返回由受信任代码返回的临时凭据，而不是经过签名的url

使用PHP，您可以

$command = $this->s3client->getCommand ('CreateMultipartUpload', array (
    'Bucket'    => $this->rootBucket,
    'Key'       => $objectName
));
$signedUrl = $command->createPresignedUrl ('+5 minutes');

但到目前为止，我还没有找到用Java实现这一点的方法。

---

对于单个PUT（或GET）操作，可以使用

generatePresignDurl

，但我不知道如何将其应用于多部分上传，就像PHP

getCommand（'createMultipartPload'/'UploadPart'/'CompleteMultipartUpload'）

方法一样，但是深入研究AWS Java SDK发现，将以下内容添加到

generateDesignedUrlRequest

中效果非常好：

AmazonS3Client amazonS3Client = /* ... */;
GeneratePresignedUrlRequest request = /* ... */;

// the following are required to trigger the multipart upload API
request.addRequestParameter("uploadId", uploadIdentifier);
request.addRequestParameter("partNumber", Integer.toString(partNumber));

// the following may be optional but are recommended to validate data integrity during upload
request.putCustomRequestHeader(Headers.CONTENT_MD5, md5Hash);
request.putCustomRequestHeader(Headers.CONTENT_LENGTH, Long.toString(contentLength));

URL presignedURL = amazonS3Client.generatePresignedUrl(request);

---

（我还没有深入挖掘以确定是需要

CONTENT\u MD5

还是

CONTENT\u LENGTH

）！希望能有更好的记录。