Android(安卓)操纵File查看文件大小，清理文件

最近在开发android应用程序的时候，socket编程中需要将一个文件的大小传输到客户端，以便计算文件的传输速度和进度。这其中要判断文件夹大小，在网上查阅资料，将有代表的demo分享下： package com.demo.file; import java.io.File;import java.text.DecimalFormat;import java.io.FileInputStream; public class GetFileSizeUtil{  private static GetFileSizeUtil instance;  public GetFileSizeUtil() {  }  public static GetFileSizeUtil getInstance() {  if (instance == null)  {   instance = new GetFileSizeUtil();  } return instance; }   public long getFileSizes(File f) throws Exception {  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; }   public long getFileSize(File f) throws Exception {  long size = 0;  File flist[] = f.listFiles();  for (int i = 0; i < flist.length; i++)  {   if (flist.isDirectory())   {    size = size + getFileSize(flist);   }   else   {    size = size + flist.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.isDirectory())   {    size = size + getlist(flist);    size--;   }  }  return size; }

/** * 清理缓存 */public void clear(File file) {File[] files = file.listFiles();if (files == null)return;for (File f : files) {f.delete();}} }

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