java - 第三方以编程方式拥有的 Amazon S3 存储桶数据下载

Question

我是 S3 的新手。我们的供应商之一与我们共享一个桶和对象。我们创建了一个 AWS 账户并将我们的团队成员添加为用户。我们可以通过 amazon aws cli 访问存储桶中的数据。我正在寻找 Java API 以编程方式下载数据。

我的代码是:

/*
 * Create your credentials file at ~/.aws/credentials (C:\Users\USER_NAME\.aws\credentials for Windows users) 
 * and save the following lines after replacing the underlined values with your own.
 *
 * [default]
 * aws_access_key_id = YOUR_ACCESS_KEY_ID
 * aws_secret_access_key = YOUR_SECRET_ACCESS_KEY
 */
AmazonS3 s3 = new AmazonS3Client();
Region usEast1 = Region.getRegion(Regions.US_EAST_1);
s3.setRegion(usEast1);
System.out.println("Downloading an object");
S3Object object = s3.getObject(new GetObjectRequest("exports.xyz.t-z", "abc/2015/12/07/62542f4f0164689f5d18cf6-2c324750-6c47-11e5-0e29-00deb82fd81f"));
System.out.println("Content-Type: "  + object.getObjectMetadata().getContentType());

错误信息是:

Downloading an object
Caught an AmazonServiceException, which means your request made it to Amazon S3, but was rejected with an error response for some reason.
Error Message:    The specified key does not exist. (Service: Amazon S3; Status Code: 404; Error Code: NoSuchKey; Request ID: 3DD21D3934A4456D)
HTTP Status Code: 404
AWS Error Code:   NoSuchKey
Error Type:       Client
Request ID:       3DD21D3934A4456D

现在如错误消息所述: key 不存在我不确定 key 是什么。数据由供应商放置到 s3。

不过，我可以使用以下代码访问数据以查看 s3 目录中列出的内容。 (也可以引用我的previous post)

System.out.println("Listing objects");
ObjectListing objectListing = s3.listObjects(
    new ListObjectsRequest().withBucketName("exports.xyz.t-z")
                            .withPrefix("abc/2015/12/07/62542f4f0164689f5d18cf6-2c324750-6c47-11e5-0e29-00deb82fd81f")
);
for (S3ObjectSummary objectSummary : objectListing.getObjectSummaries()) {
    System.out.println(" - " + objectSummary.getKey() + "  " +
            "(size = " + objectSummary.getSize() + ")");
}

下载数据的最佳推荐方式是什么？

Answer 1

看起来您正在尝试下载“目录”而不是该目录中的特定 key 。

您的代码列出了具有该前缀的对象。当您尝试使用 getObject(new GetObjectRequest()) 下载文件时，GetObjectRequest 构造函数的第二个参数必须是您调用 时返回的值之一>objectSummary.getKey().