为什么HttpStaticFileServer的netty示例使用RandomAccessFile？

Question

netty HttpStaticFileServerHandler示例使用RandomAccessFile有任何特定原因吗？

Answer 1

I think it so that they can demonstrate the use of ChunkedFile , which requires a RandomAccessFile . And the reason for that seems to be that ChunkedFile needs to be able to get the file's length.

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If I am not using https, I need not use ChunkedFile . So I can choose FileInputStream instead of RandomAccessFile which also returns a FileChannel . But I cannot get fileLength from FileInputStream which is a required input for DefaultFileRegion . So I think it is necessary to use RandomAccessFile .

That's roughly correct. However, you could potentially get the file length some other way; eg using File.length() .

Actually, it doesn't make much difference which way you get the FileChannel and the file length.

Answer 2

需要一个RAF支持零拷贝，该拷贝需要一个FileChannel，该文件通道是最经常从RAF获取的。