amazon-web-services - 更新 Amazon S3 存储桶中的文件

Question

我正在尝试将一个字符串附加到存储在 S3 中的文本文件的末尾。
目前我只是将文件的内容读入一个字符串，附加我的新文本并将文件重新保存回 S3。
有一个更好的方法吗。当文件为 >>> 10MB 时，我在想，然后读取整个文件不是一个好主意，那么我应该如何正确执行此操作？

当前代码
[代码]

private void saveNoteToFile( String p_note ) throws IOException, ServletException    
{
    String str_infoFileName =  "myfile.json"; 

    String existingNotes = s3Helper.getfileContentFromS3( str_infoFileName  ); 
    existingNotes += p_note;
    writeStringToS3( str_infoFileName , existingNotes );        
}

public void writeStringToS3(String p_fileName, String p_data) throws IOException 
{
  ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream( p_data.getBytes());

  try {
      streamFileToS3bucket(  p_fileName, byteArrayInputStream, p_data.getBytes().length);
  } 
  catch (AmazonServiceException e)
  {
      e.printStackTrace();
  } catch (AmazonClientException e)
  {
      e.printStackTrace();
  }
}

public void streamFileToS3bucket( String p_fileName,  InputStream input, long size)
{
    //Create sub folders if there is any in the file name.
    p_fileName = p_fileName.replace("\\", "/");
    if( p_fileName.charAt(0) == '/')
    {
        p_fileName = p_fileName.substring(1, p_fileName.length());
    }
    String folder = getFolderName( p_fileName );
    if( folder.length() > 0)
    {
        if( !doesFolderExist(folder))
        {
            createFolder( folder );
        }
    }
    ObjectMetadata metadata =  new ObjectMetadata();
    metadata.setContentLength(size);
    AccessControlList acl = new AccessControlList();
    acl.grantPermission(GroupGrantee.AllUsers, Permission.Read);

    s3Client.putObject(new PutObjectRequest(bucket, p_fileName , input,metadata).withAccessControlList(acl));
}

[/代码]

Answer 1

无法附加到 AWS S3 上的现有文件。当您上传一个对象时，它会创建一个新版本(如果它已经存在):

If you upload an object with a key name that already exists in the bucket, Amazon S3 creates another version of the object instead of replacing the existing object

来源: http://docs.aws.amazon.com/AmazonS3/latest/UG/ObjectOperations.html

对象是不可变的。

这些 AWS 论坛主题中也提到了这一点:

https://forums.aws.amazon.com/message.jspa?messageID=179375
https://forums.aws.amazon.com/message.jspa?messageID=540395