为什么上传到S3的文件具有内容类型application / octet-stream，除非我将文件命名为.html

Question

即使我将内容类型设置为text / html，它最终也会成为S3上的application / octet-stream。

ByteArrayInputStream contentsAsStream = new ByteArrayInputStream(contentAsBytes);
ObjectMetadata md = new ObjectMetadata();
md.setContentLength(contentAsBytes.length);
md.setContentType("text/html");
s3.putObject(new PutObjectRequest(ARTIST_BUCKET_NAME, artistId, contentsAsStream, md));

但是，如果我将文件命名为最终使用.html

s3.putObject(new PutObjectRequest(ARTIST_BUCKET_NAME, artistId + ".html", contentsAsStream, md));

然后它有效。

我的md对象是否被忽略了？我如何以编程方式绕过这个问题，因为随着时间的推移我需要上传数千个文件，因此不能直接进入S3 UI并手动修复contentType。

Answer 1

您必须在代码中执行其他操作。我刚刚使用1.9.6 S3 SDK尝试了您的代码示例，该文件获取了＆＃34; text / html＆＃34;内容类型。

这里是确切的（Groovy）代码：

class S3Test {
    static void main(String[] args) {

        def s3 = new AmazonS3Client()

        def random = new Random()
        def bucketName = "raniz-playground"
        def keyName = "content-type-test"

        byte[] contentAsBytes = new byte[1024]
        random.nextBytes(contentAsBytes)

        ByteArrayInputStream contentsAsStream = new ByteArrayInputStream(contentAsBytes);
        ObjectMetadata md = new ObjectMetadata();
        md.setContentLength(contentAsBytes.length);
        md.setContentType("text/html");
        s3.putObject(new PutObjectRequest(bucketName, keyName, contentsAsStream, md))

        def object = s3.getObject(bucketName, keyName)
        println(object.objectMetadata.contentType)
        object.close()
    }
}

程序打印

  

text / html的

S3元数据说的相同：

以下是通过网络发送的通信（由Apache HTTP Commons调试日志记录提供）：

>> PUT /content-type-test HTTP/1.1
>> Host: raniz-playground.s3.amazonaws.com
>> Authorization: AWS <nope>
>> User-Agent: aws-sdk-java/1.9.6 Linux/3.2.0-84-generic Java_HotSpot(TM)_64-Bit_Server_VM/25.45-b02/1.8.0_45
>> Date: Fri, 12 Jun 2015 02:11:16 GMT
>> Content-Type: text/html
>> Content-Length: 1024
>> Connection: Keep-Alive
>> Expect: 100-continue
<< HTTP/1.1 200 OK
<< x-amz-id-2: mOsmhYGkW+SxipF6S2+CnmiqOhwJ62WfWUkmZk4zU3rzkWCEH9P/bT1hUz27apmO
<< x-amz-request-id: 8706AE3BE8597644
<< Date: Fri, 12 Jun 2015 02:11:23 GMT
<< ETag: "6c53debeb28f1d12f7ad388b27c9036d"
<< Content-Length: 0
<< Server: AmazonS3

>> GET /content-type-test HTTP/1.1
>> Host: raniz-playground.s3.amazonaws.com
>> Authorization: AWS <nope>
>> User-Agent: aws-sdk-java/1.9.6 Linux/3.2.0-84-generic Java_HotSpot(TM)_64-Bit_Server_VM/25.45-b02/1.8.0_45
>> Date: Fri, 12 Jun 2015 02:11:23 GMT
>> Content-Type: application/x-www-form-urlencoded; charset=utf-8
>> Connection: Keep-Alive
<< HTTP/1.1 200 OK
<< x-amz-id-2: 9U1CQ8yIYBKYyadKi4syaAsr+7BV76Q+5UAGj2w1zDiPC2qZN0NzUCQNv6pWGu7n
<< x-amz-request-id: 6777433366DB6436
<< Date: Fri, 12 Jun 2015 02:11:24 GMT
<< Last-Modified: Fri, 12 Jun 2015 02:11:23 GMT
<< ETag: "6c53debeb28f1d12f7ad388b27c9036d"
<< Accept-Ranges: bytes
<< Content-Type: text/html
<< Content-Length: 1024
<< Server: AmazonS3

这也是查看source code向我们展示的行为 - 如果您设置了内容类型，则SDK不会覆盖它。

Answer 2

因为您必须在发送前使用putObject方法在设置内容类型;

        ObjectMetadata md = new ObjectMetadata();

        InputStream myInputStream = new ByteArrayInputStream(bFile); 
        md.setContentLength(bFile.length);
        md.setContentType("text/html");
        md.setContentEncoding("UTF-8");

        s3client.putObject(new PutObjectRequest(bucketName, keyName, myInputStream, md));

上传后，内容类型设置为＆＃34; text / html ＆＃34;

这是一个有效的虚拟代码，检查出来，我刚刚尝试过，它正在工作;

public class TestAWS {

    //TEST
    private static String bucketName = "whateverBucket";

    public static void main(String[] args) throws Exception {
        BasicAWSCredentials awsCreds = new BasicAWSCredentials("whatever", "whatever");

        AmazonS3 s3client = new AmazonS3Client(awsCreds);
        try
        {
            String uploadFileName = "D:\\try.txt";
            String keyName = "newFile.txt";

            System.out.println("Uploading a new object to S3 from a file\n");
            File file = new File(uploadFileName);

            //bFile will be the placeholder of file bytes
            byte[] bFile = new byte[(int) file.length()];
            FileInputStream fileInputStream=null;

            //convert file into array of bytes  
            fileInputStream = new FileInputStream(file);
            fileInputStream.read(bFile);
            fileInputStream.close();

            ObjectMetadata md = new ObjectMetadata();

            InputStream myInputStream = new ByteArrayInputStream(bFile); 
            md.setContentLength(bFile.length);
            md.setContentType("text/html");
            md.setContentEncoding("UTF-8");

            s3client.putObject(new PutObjectRequest(bucketName, keyName, myInputStream, md));
        } catch (AmazonServiceException ase)
        {
            System.out.println("Caught an AmazonServiceException, which "
                    + "means your request made it "
                    + "to Amazon S3, but was rejected with an error response"
                    + " for some reason.");
            System.out.println("Error Message:    " + ase.getMessage());
            System.out.println("HTTP Status Code: " + ase.getStatusCode());
            System.out.println("AWS Error Code:   " + ase.getErrorCode());
            System.out.println("Error Type:       " + ase.getErrorType());
            System.out.println("Request ID:       " + ase.getRequestId());
        } catch (AmazonClientException ace)
        {
            System.out.println("Caught an AmazonClientException, which "
                    + "means the client encountered "
                    + "an internal error while trying to "
                    + "communicate with S3, "
                    + "such as not being able to access the network.");
            System.out.println("Error Message: " + ace.getMessage());
        }

    }

}

希望它有所帮助。

Answer 3

It seems

  

上传文件时，AWS S3 Java客户端将尝试确定   如果还没有设置正确的内容类型。用户是   负责确保在上传时设置合适的内容类型   流。如果没有提供内容类型且无法确定   文件名，默认内容类型，“application / octet-stream”，   将被使用。

为文件提供.html扩展名提供了一种设置正确类型的方法。

根据我一直在查看的示例，您显示的代码应做您想做的事情。 ：/

Answer 4

Do you have any Override on the default mime content on your S3 account? Look at this link to see how to check it: How to override default Content Types.

Anyway, it looks like your S3 client fails to determine the correct mime-type by the content of the file, so it relies on the extension. octet-stream is the widely used default content mime type when a browser/servlet can't determine the mimetype: Is there any default mime type?

Answer 5

我可以通过命令行轻松解决此问题，即使文件名具有正确的扩展名，我也通过aws commandline上传html文件时遇到了类似的问题。

如之前的评论中所述，添加--content-type参数可以解决此问题。 执行以下命令并刷新页面返回的八位字节流。

aws s3api put-object --bucket [BUCKETNAME] --body index.html  --key index.html     --profile [PROFILE] --acl public-read 

修复：添加--content type text/html

aws s3api put-object --bucket [BUCKETNAME] --body index.html  --key index.html  --profile [PROFILE] --acl public-read --content-type text/html

Answer 6

如果您使用的是 AWS SDK for Java 2.x，则可以在构建器模式中添加内容类型。

例如，将 Base64 编码的图像作为 JPEG 对象上传到 S3（假设您已经实例化了 S3 客户端）：

byte[] stringAsByteArray = java.util.Base64.getDecoder().decode(base64EncodedString);

s3Client.putObject(
        PutObjectRequest.builder().bucket("my-bucket").key("my-key").contentType("image/jpg").build(),
        RequestBody.fromBytes(stringAsByteArray)
);