Java 如何将 InputStream 转换为 FileInputStream
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How to convert InputStream to FileInputStream
提问by Frank
I have this line in my program :
我的程序中有这一行：
InputStream Resource_InputStream=this.getClass().getClassLoader().getResourceAsStream("Resource_Name");
But how can I get FileInputStream from it [Resource_InputStream] ?
但是我怎么能从中得到 FileInputStream [Resource_InputStream] 呢？
采纳答案by BalusC
Use ClassLoader#getResource()instead if its URI represents a valid local disk file system path.
ClassLoader#getResource()如果其 URI 表示有效的本地磁盘文件系统路径，请改用。
URL resource = classLoader.getResource("resource.ext");
File file = new File(resource.toURI());
FileInputStream input = new FileInputStream(file);
// ...
If it doesn't (e.g. JAR), then your best bet is to copy it into a temporary file.
如果没有（例如 JAR），那么最好的办法是将它复制到一个临时文件中。
Path temp = Files.createTempFile("resource-", ".ext");
Files.copy(classLoader.getResourceAsStream("resource.ext"), temp, StandardCopyOption.REPLACE_EXISTING);
FileInputStream input = new FileInputStream(temp.toFile());
// ...
That said, I really don't see any benefit of doing so, or it must be required by a poor helper class/method which requires FileInputStreaminstead of InputStream. If you can, just fix the API to ask for an InputStreaminstead. If it's a 3rd party one, by all means report it as a bug. I'd in this specific case also put question marks around the remainder of that API.
也就是说，我真的没有看到这样做的任何好处，或者它必须由一个需要FileInputStream而不是InputStream. 如果可以，只需修复 API 以请求InputStream替代。如果是第 3 方，请务必将其报告为错误。在这种特定情况下，我还会在该 API 的其余部分周围加上问号。
回答by whiskeysierra
Long story short: Don't use FileInputStreamas a parameter or variable type. Use the abstract base class, in this case InputStream instead.
长话短说： 不要使用 FileInputStream作为参数或变量类型。使用抽象基类，在本例中为 InputStream。
回答by Nenad Bulatovic
You need something like:
你需要这样的东西：
URL resource = this.getClass().getResource("/path/to/resource.res");
File is = null;
try {
is = new File(resource.toURI());
} catch (URISyntaxException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
try {
FileInputStream input = new FileInputStream(is);
} catch (FileNotFoundException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
But it will work only within your IDE, not in runnable JAR. I had same problem explained here.
但它只能在您的 IDE 中工作，而不能在可运行的 JAR 中工作。我在这里解释了同样的问题。
