Convert InputStream to byte array in Java

Question

How do I read an entire InputStream into a byte array?

Answer 1

Use vanilla Java's DataInputStream and its readFully Method (exists since at least Java 1.4):

...
byte[] bytes = new byte[(int) file.length()];
DataInputStream dis = new DataInputStream(new FileInputStream(file));
dis.readFully(bytes);
...

There are some other flavors of this method, but I use this all the time for this use case.