[FIXED] How to get an excel file from AWS S3 bucket into a MultipartFile in Java

Issue

I've been trying to extract an .xlsx file from a AWS bucket I created and store it as a multipartfile variable. I've tried many different approaches, but at best I get weird characters. I'm not finding much documentation on how to do this. Thanks!

Solution

// you may need to initialize this differently to get the correct authorization
final AmazonS3Client s3Client = AmazonS3ClientBuilder.defaultClient(); 
final S3Object object = s3Client.getObject("myBucket", "fileToDownload.xlsx");

// with Java 7 NIO
final Path filePath = Paths.get("localFile.xlsx");
Files.copy(object.getObjectContent(), filePath);
final File localFile = filePath.toFile();

// or Apache Commons IO
final File localFile = new File("localFile.xlsx");
FileUtils.copyToFile(object.getObjectContent(), localFile);

I'm not 100% sure what you mean by "MultipartFile" - that's usually in the context of a file that's been sent to your HTTP web service via a multipart POST or PUT. The file you're getting from S3 is technically part of the response to an HTTP GET request, but the Amazon Java Library abstracts this away for you, and just gives you the results as an InputStream.

Answered By - Andrew Rueckert
Answer Checked By - David Goodson (JavaFixing Volunteer)