public class FileUtil
{
 
 //把一个文件从一位置复制到另一位置
 public static void copy(File sourFile, File destFile)
 {
  int BUFF_SIZE = 100000;
  byte[] buffer = new byte[BUFF_SIZE];
  InputStream in = null;
  OutputStream _out = null;
  try
  {
   if (!destFile.exists())
   {
    destFile.createNewFile();
   }
   in = new FileInputStream(sourFile);
   _out = new FileOutputStream(destFile);
   while (true)
   {
    synchronized (buffer)
    {
     int amountRead = in.read(buffer);
     if (amountRead == -1)
     {
      break;
     }
     _out.write(buffer, 0, amountRead);
    }
   }
  }
  catch (Exception ex)
  {
   //return ex.getMessage();
            ex.printStackTrace();
  }
  finally
  {
   try
   {
    if (in != null)
    {
     in.close();
    }
    if (_out != null)
    {
     _out.close();
    }
   }
   catch (Exception ex)
   {
    //return ex.getMessage();
                ex.printStackTrace();
   }
  }
 }
 //随机创建一个不包含扩展符的文件名
 public static String createFileName()
 {
  String newFileName = "";
  java.util.Date dt = new java.util.Date();
  newFileName = "file_";
  newFileName = newFileName + dt.getTime();
  return newFileName;
 }
 public static void main(String[] args)
 {
  System.out.println("Hello World!");
  File a = new File("d:\\drwtsn32.log");
  File b = new File("d:\\b.txt");
  FileUtil.copy(a,b);
 }
}