标记和重置不适用于bufferedinputStream

Question

我正在尝试读取输入流两次。但是当我尝试重置流并读取它时说没有字节read.i从inputstream更改为bufferedinputstream仍然重置对我不起作用。可能是我正在做的错误？下面是我的代码：

byte[] buffer = new byte[READ_BUFFER_SIZE];
int bytesRead=0;
        InputStream _baseStream =  new FileInputStream("slot.txt");
        BufferedInputStream buff =new BufferedInputStream(_baseStream);
        try {

            bytesRead = buff.read(buffer, 0, READ_BUFFER_SIZE);
            System.out.println("1. "+bytesRead);
        } catch (IOException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        }
        if(bytesRead>0)
        {
            buff.mark(10);
            buff.reset();
            try {
                //bytesRead = _baseStream.read(buffer, 0, READ_BUFFER_SIZE);
                bytesRead = buff.read(buffer, 0, READ_BUFFER_SIZE);
                System.out.println("2. "+bytesRead);
            } catch (IOException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            }
        }

输出 1. 39 2. -1