JAVA計算文件(夾)File類型的大小(文件個數)

/**
 * 
 * @author esle
 *
 */
public class FileUtis {

    public static String FormetFileSize(long fileS) {// 轉換文件大小
        DecimalFormat df = new DecimalFormat("#.00");
        String fileSizeString = "";
        if (fileS < 1024) {
            fileSizeString = df.format((double) fileS) + "B";
        } else if (fileS < 1048576) {
            fileSizeString = df.format((double) fileS / 1024) + "K";
        } else if (fileS < 1073741824) {
            fileSizeString = df.format((double) fileS / 1048576) + "M";
        } else {
            fileSizeString = df.format((double) fileS / 1073741824) + "G";
        }
        return fileSizeString;
    }
}

public long getFileSize(File file) throws Exception{//文件大小
        long size=0;
        if (file.exists()) {
            FileInputStream fis = null;
            fis = new FileInputStream(f);
           size= fis.available();
        } else {
            file.createNewFile();
            System.out.println("文件不存在");
        }
        return size;
    }

  public long getFileSize(File folder)throws Exception//取得文件夾大小
    {
        long size = 0;
        File flist[] = folder.listFiles();
        for (int i = 0; i < flist.length; i++)
        {
            if (flist[i].isDirectory())
            {
                size = size + getFileSize(flist[i]);
            } else
            {
                size = size + flist[i].length();
            }
        }
        return size;
    }

 public long getlist(File f){//遞歸求取目錄文件個數
        long size = 0;
        File flist[] = f.listFiles();
        size=flist.length;
        for (int i = 0; i < flist.length; i++) {
            if (flist[i].isDirectory()) {
                size = size + getlist(flist[i]);
                size--;
            }
        }
        return size;
    }
 }

計算時間差

long startTime= System.currentTimeMillis();
long endTime = System.currentTimeMillis();
        System.out.println("總共花費時間爲：" + (endTime - startTime) + "毫秒...");