为 Java 中的文件生成 Azure SAS 令牌：签名字段格式不正确

Question

我正在尝试在 Java 中为 Azure Data Lake Gen. 2 存储帐户访问错误，但每次生成的令牌都不正确.

已经讨论了类似的问题，但是使用了旧版本的 Azure SDK 并手动创建了签名。 我正在使用最新版本azure-storage-8.6.3 ，但也尝试了8.0.0和7.0.0 ，但均未成功。

这是我的代码：

public class SasTokenExample {

    public static String generateSasToken(URI fileUri) throws StorageException, URISyntaxException, InvalidKeyException {
        StorageCredentials credentials = new StorageCredentialsAccountAndKey("myaccount", "thisisnottheac+tualkeybutonlyanexampletode+monstratewhatsgoingonhere+12+34567890123456==");
        CloudFile file = new CloudFile(fileUri, credentials);

        SharedAccessFilePolicy policy = new SharedAccessFilePolicy();
        policy.setPermissions(EnumSet.of(SharedAccessFilePermissions.READ));
        policy.setSharedAccessStartTime(null);
        policy.setSharedAccessExpiryTime(getExpirationTime());

        return file.generateSharedAccessSignature(policy, null);
    }

    private static Date getExpirationTime() {
        LocalDateTime expLDT = LocalDateTime.now().plusMinutes(30);
        Instant expInstant = expLDT.atZone(ZoneId.systemDefault()).toInstant();
        return Date.from(expInstant);
    }

    public static void main(String[] args) throws URISyntaxException, InvalidKeyException, StorageException, MalformedURLException {
        URI uri = new URI("http://myaccount.blob.core.windows.net/mycontainer/my.file");
        System.out.println(uri.toString() + "?" + generateSasToken(uri));
    }
}

从那，我得到这样的网址：

http://myaccount.blob.core.windows.net/mycontainer/my.file?sig=ngk3fX081paEHbYDcmf7f2Zkp6ZbYUSlshYLB2O%2F3%2B0%3D&se=2020-05-08T16%3A49%3A23Z&sv=2019-02-02&sp=r&sr=f

当我在浏览器中打开链接时，我得到以下结果：

<?xml version="1.0" encoding="utf-8"?>
<Error>
  <Code>AuthenticationFailed</Code>
  <Message>Server failed to authenticate the request. Make sure the value of Authorization header is formed correctly including the signature. 
RequestId:3dfc7fb8-701e-0057-2054-25add3000000
Time:2020-05-08T16:19:28.4764866Z</Message>
  <AuthenticationErrorDetail>Signature fields not well formed.</AuthenticationErrorDetail>
</Error>

Answer 1

我相信您的问题是您正在使用SharedAccessFilePolicy为blob资源（Data Lake Gen2 资源本质上是 blob）生成 SAS URL。 您将需要使用SharedAccessBlobPolicy 。 所以你的代码是：

    CloudBlob file = new CloudBlob (fileUri, credentials);
    SharedAccessBlobPolicy policy = new SharedAccessBlobPolicy ();
    policy.setPermissions(EnumSet.of(SharedAccessBlobPermissions.READ));
    policy.setSharedAccessStartTime(null);
    policy.setSharedAccessExpiryTime(getExpirationTime());

    return file.generateSharedAccessSignature(policy, null);

试一试，它应该可以工作。