java 判断文件夹大小

public static void main(String[] args) throws IOException{
  long all = getSize(new File("D:\\file"));
  System.out.println(all);
 }
 //判断文件夹大小
 public static long getSize(File file){ 
        //判断文件是否存在 
        if(file.exists()){  
            if (!file.isFile()) { 
                //获取文件大小 
                File[] fl = file.listFiles(); 
                long ss = 0; 
                for (File f : fl) 
                    ss += getSize(f); 
                return ss; 
            } else { 
             long ss = file.length(); 
                return ss; 
            } 
        }else{ 
            return 0; 
        } 
    }