问题
I have read this post How to convert InputStream to FileInputStream on converting a InputStream into a FileInputStream. However, the answer does not work if you are using a resource that is in a jar file. Is there another way to do it.
I need to do this to get the FileChannel from a call to
Object.class.getResourceAsStream(resourceName);
回答1:
You can't, without basically writing to a file. Unless there's a file, there can't be a FileInputStream or a FileChannel. If at all possible, make sure your code is agnostic to the input source - design it in terms of InputStream and ByteChannel (or whatever kind of channel is most appropriate).
回答2:
From the InputStream returned by Class.getResourceAsStream(), you can make a Channel with Channels.newChannel( InputStream ).
This is not the FileChannel you requested, but it is still a Channel. Is it sufficient to meet your needs?
回答3:
If you really need a file and you know that the resource is not inside a jar or loaded remotely, then you can use getResource instead.
URL resourceLocation = Object.class.getResource(resourcePath);
if (resourceLocation == null) { throw new FileNotFoundException(resourcePath); }
File myFile = new File(resourceLocation.toURI());
If you don't absolutely need a FileChannel or can't make assumptions about how your classpath is laid out, then Andy Thomas-Cramer's solution is probably the best.
来源：https://stackoverflow.com/questions/5355040/convert-inputstream-into-fileinputstream