Create a file from a ByteArrayOutputStream

Question

Can someone explain how I can get a file object if I have only a ByteArrayOutputStream. How to create a file from a ByteArrayOutputStream?

Chaddie

Answer 1

You can do it with using a FileOutputStream and the writeTo method.

ByteArrayOutputStream byteArrayOutputStream = getByteStreamMethod();
try(OutputStream outputStream = new FileOutputStream("thefilename")) {
    byteArrayOutputStream.writeTo(outputStream);
}

Source: "Creating a file from ByteArrayOutputStream in Java." on Code Inventions

Alake

@MarkusMikkolainen yeah ..obviously :) – Alake

Or use java 7 try with resources statement to completely get rid off finally block;) #2016799 – Crozier

bro what if i dont have "thefilename" , insted i have byte[] stream of that excel, then what is the way? – Kosher

Answer 2

You can use a FileOutputStream for this.

FileOutputStream fos = null;
try {
    fos = new FileOutputStream(new File("myFile")); 
    ByteArrayOutputStream baos = new ByteArrayOutputStream();

    // Put data in your baos

    baos.writeTo(fos);
} catch(IOException ioe) {
    // Handle exception here
    ioe.printStackTrace();
} finally {
    fos.close();
}

Belgravia

Your code won't work with fos in try block. Also, new File() is not required. – Hegumen

It's a good thing he added "new File()". It's easier for the reader to know there's a File constructor available. – Ylem

This seems to be needed for Android. – Mechanistic

Can be improved with fos inside try-with-resources () and dropping the finally – Odaniel