Convert Bytes to KB, MB, GB, TB - java

Converter.java

public class Converter{
    static long kilo = 1024;
    static long mega = kilo * kilo;
    static long giga = mega * kilo;
    static long tera = giga * kilo;
    
    public static void main(String[] args) {
        for (String arg: args) {
            try {
                System.out.println(getSize(Long.parseLong(arg)));
            } catch(NumberFormatException e) {
                System.out.println(arg + " is not a long");
            }
        }
    }
    
    public static String getSize(long size) {
        String s = "";
        double kb = (double)size / kilo;
        double mb = kb / kilo;
        double gb = mb / kilo;
        double tb = gb / kilo;
        if(size < kilo) {
            s = size + " Bytes";
        } else if(size >= kilo && size < mega) {
            s =  String.format("%.2f", kb) + " KB";
        } else if(size >= mega && size < giga) {
            s = String.format("%.2f", mb) + " MB";
        } else if(size >= giga && size < tera) {
            s = String.format("%.2f", gb) + " GB";
        } else if(size >= tera) {
            s = String.format("%.2f", tb) + " TB";
        }
        return s;
    }
}

@Cranked Nice and clean ... but expensive! Do NOT use in (tight) loops.

Mixed alternative:

public class ByteUnitFormatter {
  private static final int THRESHOLD = 1024; // You could use 2048, 4096 or 8192 for greater precision / lower unit.

  private static final String[] UNITS = new String[]{ "B", "KB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB" };

  public static void main( String[] args ) {
    for( String arg : args ) {
      try {
        System.out.println( format( Long.parseLong( arg ), 2 ) );
      } catch (NumberFormatException e) {
        System.out.println( arg + " is not a long" );
      }
    }
  }

  public static String format( double size, int decimals ) {
    size = size < 0 ? 0 : size;
    int u;
    for( u = 0; u < UNITS.length - 1 && size >= THRESHOLD; ++u ) {
      size /= 1024;
    }
    return String.format( "%." + decimals + "f %s", size, UNITS[ u ] );
  }
}