求出目录的大小

import java.io.File;
import java.util.Scanner;

public class DirectorySize {
    public static void main(String[] args){
        System.out.print("Enter a directory or a file: ");
        Scanner input = new Scanner(System.in);
        String directory = input.nextLine();
        
        System.out.println(getSize(new File(directory)) + " bytes");    
    }
    
    public static long getSize(File file){
        long size = 0;
        
        if(file.isDirectory())
        {
            File[] files = file.listFiles(); // All files and Subdirectories
            for(int i = 0; i < files.length; i++)
            {
                size += getSize(files[i]);
            }
        }
        else
        {
            size += file.length();    
        }
        return size;
    }
}