Question

我正在使用ReadableByteChannel来读取文件。

代码段如下

   InputStream in = new FileInputStream("Copy.tiff");
   FileInputStream in1 = new FileInputStream("Copy.tiff");
   FileChannel inChannel = in1.getChannel();
   ReadableByteChannel srcChannel = null;
   srcChannel = Channels.newChannel(in);
   ByteBuffer buffer = ByteBuffer.allocate(1024);
   long pos1 = 0;
   buffer.rewind();
   pos1= srcChannel.read(buffer);//Here value is -1
   pos1 = inChannel.read(buffer);//Here some positive number

如果我使用InputStream，则read方法总是返回-1。如果我使用FileInputStream它返回一个正数。谷歌搜索没有提供任何适当的答案。任何关于出错的反馈。

Answer 1

我无法重现（在Windows上）。我通过这两种方法获得了正值，但我不明白它为什么会失败。也许这是一个非常糟糕的依赖于实现的怪癖。

FileChannel（由FileInputStream.getChannel（）返回）已经实现了ReadableByteChannel，所以我想知道你为什么要手动创建一个？

Answer 2

以下代码适用于我：

    ByteBuffer buffer = ByteBuffer.allocate(1024);
    InputStream in = new FileInputStream("Copy.tiff");
    ReadableByteChannel srcChannel = Channels.newChannel(in);
    long pos = srcChannel.read(buffer);
    System.out.println("Position in channel: " + pos);

Answer 3

ReadableByteChannel srcChannel = new FileInputStream("Copy.tiff).getChannel();

ReadableBytechannel.read始终返回-1

3 个答案: