java计算文件大小 java获取文件大小

package tony;
 import java.io.File;
 import java.text.DecimalFormat;
 import java.io.FileInputStream;public class GetFileSize
 {
     public long getFileSizes(File f) throws Exception{//取得文件大小
         long s=0;
         if (f.exists()) {
             FileInputStream fis = null;
             fis = new FileInputStream(f);
            s= fis.available();
         } else {
             f.createNewFile();
             System.out.println("文件不存在");
         }
         return s;
     }
     // 递归
     public long getFileSize(File f)throws Exception//取得文件夹大小
     {
         long size = 0;
         File flist[] = f.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 String FormetFileSize(long fileS) {//转换文件大小
         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 getlist(File f){//递归求取目录文件个数
         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--;
             }
         }
           }
    
     public static void main(String args[])
     {
         GetFileSize g = new GetFileSize();
         long startTime = System.currentTimeMillis();
         try
         {
             long l = 0;
             String path = "C:\\WINDOWS";
             File ff = new File(path);
             if (ff.isDirectory()) { //如果路径是文件夹的时候
                 System.out.println("文件个数           " + g.getlist(ff));
                 System.out.println("目录");
                 l = g.getFileSize(ff);
                 System.out.println(path + "目录的大小为：" + g.FormetFileSize(l));
             } else {
                 System.out.println("     文件个数           1");
                 System.out.println("文件");
                 l = g.getFileSizes(ff);
                 System.out.println(path + "文件的大小为：" + g.FormetFileSize(l));
             }
            
         } catch (Exception e)
         {
             e.printStackTrace();
         }
         long endTime = System.currentTimeMillis();
         System.out.println("总共花费时间为：" + (endTime - startTime) + "毫秒...");
     }
 }