How to convert byte size into human readable format in java?

Question

How to convert byte size into human-readable format in Java? Like 1024 should become "1 Kb" and 1024*1024 should become "1 Mb".I am kind of sick of writing this utility method for each project. Are there any static methods in Apache Commons for this?

Answer 1

While I don't know if apache commons has anything like this, but you can easily write a static helper class that has this function inside of it:

public static String fileSize(double bytes, boolean si) {

int thresh = si ? 1000 : 1024;

if (Math.abs(bytes) < thresh) {

return bytes + "B";

}

String[] units = (si ? new String[] { "kB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB" }

: new String[] { "KiB", "MiB", "GiB", "TiB", "PiB", "EiB", "ZiB", "YiB" });

int u = -1;

do {

bytes /= thresh;

++u;

} while (Math.abs(bytes) >= thresh && u < units.length - 1);

return String.format("%.1f", bytes) + "" + units[u];

}

This will continually divide the input double bytes until it becomes lower than the threshold, and each division will increase the index of the String array that holds the units.