java 将 InputStream 转换为 FileInputStream
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Convert InputStream into FileInputStream
提问by user489041
I have read this post How to convert InputStream to FileInputStreamon 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.
我已经阅读了这篇文章如何将 InputStream 转换为 FileInputStream将 InputStream 转换为 FileInputStream。但是，如果您使用的是 jar 文件中的资源，则答案不起作用。有没有其他方法可以做到。
I need to do this to get the FileChannelfrom a call to
Object.class.getResourceAsStream(resourceName);
我需要这样做才能FileChannel从呼叫中获得
Object.class.getResourceAsStream(resourceName);
回答by Jon Skeet
You can't, without basically writing to a file. Unless there's a file, there can't be a FileInputStreamor a FileChannel. If at all possible, make sure your code is agnostic to the input source - design it in terms of InputStreamand ByteChannel(or whatever kind of channel is most appropriate).
你不能，基本上没有写入文件。除非有文件，否则不能有 aFileInputStream或FileChannel. 如果可能，请确保您的代码与输入源无关 - 根据InputStream和ByteChannel（或任何最合适的通道）进行设计。
回答by Andy Thomas
From the InputStream returned by Class.getResourceAsStream(), you can make a Channel with Channels.newChannel( InputStream ).
从 Class.getResourceAsStream() 返回的 InputStream，您可以使用Channels.newChannel( InputStream )创建一个 Channel 。
This is not the FileChannel you requested, but it is still a Channel. Is it sufficient to meet your needs?
这不是您请求的 FileChannel，但它仍然是一个 Channel。是否足以满足您的需求？
回答by Mike Samuel
If you really need a file and you know that the resource is not inside a jar or loaded remotely, then you can use getResourceinstead.
如果您确实需要一个文件并且您知道该资源不在 jar 中或远程加载，那么您可以getResource改用。
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 FileChannelor can't make assumptions about how your classpath is laid out, then Andy Thomas-Cramer's solution is probably the best.
如果您不是绝对需要FileChannel或无法对类路径的布局方式做出假设，那么 Andy Thomas-Cramer 的解决方案可能是最好的。
