Java发送和接收文件工作不正常

Question

我的密码是

public void sendFile () throws IOException {
        DataOutputStream dataOutputStream = new DataOutputStream(socket.getOutputStream());
        byte[] buffer = new byte[4096];
        FileInputStream fileInputStream = new FileInputStream("\"C:\\Users\\abdul\\Desktop\\Instructions.txt\"");
        int bytes = fileInputStream.read(buffer,0,buffer.length);
        dataOutputStream.write(buffer,0,bytes);
    }
private void receiveFile() throws Exception{
        DataInputStream dataInputStream = new DataInputStream(socket.getInputStream());
        byte[] buffer = new byte[Integer.MAX_VALUE];
        int bytes = dataInputStream.read(buffer,0,buffer.length);
        FileOutputStream fileOutputStream = new FileOutputStream("Instructions.txt");
        fileOutputStream.write(buffer,0,bytes);
    }

我没有收到错误，但当我运行程序时，使用receiveFile的类的输出只是spam null。我只需要从服务器向客户端发送一个文件