不多说，上代码：

//复制文件
 public static void CopyFile(String fromfile,String tofile){
  try {
   FileInputStream fosfrom = new java.io.FileInputStream(fromfile);
   FileOutputStream fosto = new FileOutputStream(tofile);
   byte bt[] = new byte[1024];
   int c;
   while ((c = fosfrom.read(bt)) > 0) {
      fosto.write(bt, 0, c); //将内容写到新文件当中
   }
   fosfrom.close();
      fosto.close();
  } catch (FileNotFoundException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  } catch (IOException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
 }