问题
Is it possible to obtain the File being used by a FileInputStream? FileInputStream does not appear to have any methods for retrieving it.
回答1:
There are no direct methods in FileInputStream API, but if you really wanted, you can use java reflection API to get the path (actual file name with full path) as shown below:
FileInputStream fis = new FileInputStream(inputFile);
Field field = fis.getClass().getDeclaredField("path");
field.setAccessible(true);
String path = (String)field.get(fis);
System.out.println(path);
The path variable (holds the file name with path) is declared in the FileInputStream class as a private final field, which we are getting it using reflections code as shown above.
P.S.: You need to NOTE that the above approach can't be guaranteed to achieve the result across all of the JVM implementations as it is not defined in the specification.
来源：https://stackoverflow.com/questions/40700958/getting-the-file-used-by-a-fileinputstream