import java.io.File;

public class GetDirectorySize {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		File file = new File("C:\\test");
		if (file.exists()) {
		    double bytes = file.length();
		    double kilobytes = (bytes / 1024);
		    double megabytes = (kilobytes / 1024);
		    double gigabytes = (megabytes / 1024);

		    System.out.println("bytes : " + bytes);
		    System.out.println("kilobytes : " + kilobytes);
		    System.out.println("megabytes : " + megabytes);
		    System.out.println("gigabytes : " + gigabytes);
		} else {
		    System.out.println("File does not exists!");
		}
	}

}