java 获取文件夹大小，文件大小，文件个数

http://blog.sina.com.cn/s/blog_45096c6a0100btse.html

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--;
            }
        }
        return 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...");
    }
}

用java删除文件夹里的所有文件

import java.io.File;

public class Test
{
   public static void main(String args[]){
       Test t = new Test();
       delFolder("c:/bb");
       System.out.println("deleted");
}

//删除文件夹
//param folderPath 文件夹完整绝对路径

     public static void delFolder(String folderPath) {
     try {
        delAllFile(folderPath); //删除完里面所有内容
        String filePath = folderPath;
        filePath = filePath.toString();
        java.io.File myFilePath = new java.io.File(filePath);
        myFilePath.delete(); //删除空文件夹
     } catch (Exception e) {
       e.printStackTrace(); 
     }
}

//删除指定文件夹下所有文件
//param path 文件夹完整绝对路径
   public static boolean delAllFile(String path) {
       boolean flag = false;
       File file = new File(path);
       if (!file.exists()) {
         return flag;
       }
       if (!file.isDirectory()) {
         return flag;
       }
       String[] tempList = file.list();
       File temp = null;
       for (int i = 0; i < tempList.length; i++) {
          if (path.endsWith(File.separator)) {
             temp = new File(path + tempList[i]);
          } else {
              temp = new File(path + File.separator + tempList[i]);
          }
          if (temp.isFile()) {
             temp.delete();
          }
          if (temp.isDirectory()) {
             delAllFile(path + "/" + tempList[i]);//先删除文件夹里面的文件
             delFolder(path + "/" + tempList[i]);//再删除空文件夹
             flag = true;
          }
       }
       return flag;
     }
}