Byte[] to File in Java

byte[] to file in Java

Use Apache Commons IO

FileUtils.writeByteArrayToFile(new File("pathname"), myByteArray)

Or, if you insist on making work for yourself...

try (FileOutputStream fos = new FileOutputStream("pathname")) {
   fos.write(myByteArray);
   //fos.close(); There is no more need for this line since you had created the instance of "fos" inside the try. And this will automatically close the OutputStream
}

Convert bytes[] to 'File' in Java

 try (FileOutputStream fileOuputStream = new FileOutputStream("filename")){
    fileOuputStream.write(byteArray);
 }

Byte array to File object without saving to disk

That's not how it works. a java.io.File object is a light wrapper: Check out the source code - it's got a String field that contains the path and that is all it has aside from some bookkeeping stuff.

It is not possible to represent arbitrary data with a java.io.File object. j.i.File objects represent literal files on disk and are not capable of representing anything else.

Files.readAllBytes gets you the contents from the bytes, that's.. why the method has that name.

The usual solution is that a method in some library that takes a File is overloaded; there will also be a method that takes a byte[], or, if that isn't around, a method that takes an InputStream (you can make an IS from a byte[] easily: new ByteArrayInputStream(byteArr) will do the job).

If the API you are using doesn't contain any such methods, it's a bad API and you should either find something else, or grit your teeth and accept that you're using a bad API, with all the workarounds that this implies, including having to save bytes to disk just to satisfy the asinine API.

But look first; I bet there is a byte[] and/or InputStream variant (or possibly URL or ByteBuffer or ByteStream or a few other more exotic variants).

File to byte[] in Java

It depends on what best means for you. Productivity wise, don't reinvent the wheel and use Apache Commons. Which is here FileUtils.readFileToByteArray(File input).

How can I write a byte array to a file in Java?

You can use IOUtils.write(byte[] data, OutputStream output) from Apache Commons IO.

KeyGenerator kgen = KeyGenerator.getInstance("AES");
kgen.init(128);
SecretKey key = kgen.generateKey();
byte[] encoded = key.getEncoded();
FileOutputStream output = new FileOutputStream(new File("target-file"));
IOUtils.write(encoded, output);

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