文件大小格式化(java)

 public static String formatFileSize(String strFileSize)

{
  long fileSize = Long.parseLong(strFileSize);
  String showSize = "";
  
  if(fileSize>=0 && fileSize<1024)

  {
   showSize = strFileSize + "B";
  }
  else if(fileSize>=1024 && fileSize<(1024*1024))

 {
   showSize = Long.toString(fileSize/1024) + "KB";
  }
  else if(fileSize>=(1024*1024) && fileSize<(1024*1024*1024))

 {
   showSize = Long.toString(fileSize/(1024*1024)) + "MB";
  }
  else if(fileSize>=(1024*1024*1024))

 {
   showSize = Long.toString(fileSize/(1024*1024*1024)) + "GB";
  } 
  return showSize;
 }