AmazonS3 putObject与InputStream的长度例如 [英] AmazonS3 putObject with InputStream length example
问题描述
我将文件上载到S3用java - 这是我到目前为止已有:
AmazonS3 S3 =新AmazonS3Client(新BasicAWSCredentials(XX,YY));
名单<斗>水桶= s3.listBuckets();
s3.putObject(新PutObjectRequest(buckets.get(0).getName(),文件名,流,新ObjectMetadata()));
该文件被上传,但是当我不设置内容长度则会出现警告:
com.amazonaws.services.s3.AmazonS3Client putObject:为流&gt没有指定内容长度;数据。流内容将被缓存在内存中,并可能导致内存不足的错误。
这是一个文件,我上传和流
变量是的InputStream
,从中我可以得到这样的字节数组: IOUtils.toByteArray(流)
所以,当我尝试设置内容长度和MD5(此处取自 )是这样的:
//获取MD5哈希值的base64
消息摘要消息摘要= MessageDigest.getInstance(MD5);
messageDigest.reset();
messageDigest.update(IOUtils.toByteArray(流));
byte []的resultByte = messageDigest.digest();
字符串hashtext =新的String(Hex.en $ C $环己烷(resultByte));
ObjectMetadata元=新新ObjectMetadata();
meta.setContentLength(IOUtils.toByteArray(流).length);
meta.setContentMD5(hashtext);
这将导致以下错误回来从S3:
您指定的内容,MD5是无效的。
我是什么做错了吗?
任何帮助AP preciated!
PS 我在谷歌应用程序引擎 - 我无法将文件写入到磁盘或<一href="http://www.java2s.com/$c$c/JavaAPI/java.io/FilecreateTempFileString$p$pfixStringsuffix.htm">create一个临时文件因为AppEngine上不支持的FileOutputStream。
监守原来的问题一直没有回答,我只好碰到同样的问题,对于MD5问题的解决方案是,S3不希望的十六进制EN codeD字符串的MD5我们通常思考的问题。
相反,我不得不这样做。
//内容是传递的InputStream
byte []的resultByte = DigestUtils.md5(内容);
字符串streamMD5 =新的String(Base64.en codeBase64(resultByte));
metaData.setContentMD5(streamMD5);
从本质上讲,他们想要的MD5值什么的Base64 EN codeD原始MD5的字节数组,而不是十六进制字符串。当我切换到这一点,开始为我伟大的工作。
I am uploading a file to S3 using java -- this is what I got so far:
AmazonS3 s3 = new AmazonS3Client(new BasicAWSCredentials("XX","YY"));
List<Bucket> buckets = s3.listBuckets();
s3.putObject(new PutObjectRequest(buckets.get(0).getName(), fileName, stream, new ObjectMetadata()));
The file is being uploaded but a WARNING is raised when I am not setting the content length:
com.amazonaws.services.s3.AmazonS3Client putObject: No content length specified for stream > data. Stream contents will be buffered in memory and could result in out of memory errors.
This is a file I am uploading and the stream
variable is an InputStream
, from which I can get the byte array like this: IOUtils.toByteArray(stream)
.
So when I try to set the content length and MD5 (taken from here) like this:
// get MD5 base64 hash
MessageDigest messageDigest = MessageDigest.getInstance("MD5");
messageDigest.reset();
messageDigest.update(IOUtils.toByteArray(stream));
byte[] resultByte = messageDigest.digest();
String hashtext = new String(Hex.encodeHex(resultByte));
ObjectMetadata meta = new new ObjectMetadata();
meta.setContentLength(IOUtils.toByteArray(stream).length);
meta.setContentMD5(hashtext);
It causes the following error to come back from S3:
The Content-MD5 you specified was invalid.
What am I doing wrong?
Any help appreciated!
P.S. I am on Google App Engine - I cannot write the file to disk or create a temp file because AppEngine does not support FileOutputStream.
Becuase the original question was never answered, and I had to run into this same problem, the solution for the MD5 problem is that S3 doesn't want the Hex encoded MD5 string we normally think about.
Instead, I had to do this.
// content is a passed in InputStream
byte[] resultByte = DigestUtils.md5(content);
String streamMD5 = new String(Base64.encodeBase64(resultByte));
metaData.setContentMD5(streamMD5);
Essentially what they want for the MD5 value is the Base64 encoded raw MD5 byte-array, not the Hex string. When I switched to this it started working great for me.
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