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I am trying to access an excel file from my res/raw folder, and I know that you can only really do this using an InputStream; however, the XSSFWorkbook commands in Apache POI only take FileInputStreams and not InputStreams: is there any way to do this? I've tried using the following code but go this error: java.lang.NullPointerException: Attempt to invoke virtual method 'java.net.URI java.net.URL.toURI()' on a null object reference

Here is the code I've tried using:

     URL ins = this.getClass().getResource("ncaa.xlsx");
 FileInputStream file = new FileInputStream(new File(ins.toURI()));
 XSSFWorkbook workbook = new XSSFWorkbook(file);
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    Well your first problem is that you can't get the resource for ncaa.xlsx - ins is null. So before you think about anything else, you should get that part working. Commented Jul 5, 2015 at 18:08

2 Answers 2

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is there any way to do this?

Copy the raw resource out to a file, then open the file and hand the FileInputStream over to the library.

I've tried using the following

getResource() has nothing to do with Android resources. To access an InputStream on a raw resource, use getResources().openRawResource(), called on your Activity or other handy Context.

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Thanks for the quick answer, but will handing-off method still work even when the app is published (where it can't access the file)?
@JacobPlatin: I am sorry, but I do not know what your comment is referring to. If you wish to use a library that only accepts a file, then you need a file. How you get that file is up to you. You indicated that you were packaging the spreadsheet as a raw resource, and I indicated that you would then have to copy the raw resource to a file. You are welcome to get the file by some other means (e.g., download it from the Internet). Or, do not ship a spreadsheet in the first place, but convert it into some data that is easier to process.
No problem, I actually answered my own question; I apologize
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As explained fairly clearly in the Apache POI documentation, don't use an InputStream if you have a file! Using a file is both quicker and lower memory, so should be very much preferred over a stream, especially if you have a File to start with!

As per the Apache POI documentation on Files vs Streams, instead of your current code:

URL ins = this.getClass().getResource("ncaa.xlsx");
FileInputStream file = new FileInputStream(new File(ins.toURI()));
XSSFWorkbook workbook = new XSSFWorkbook(file);

You should instead make it something like:

URL ins = this.getClass().getResource("ncaa.xlsx");
if (ins == null) 
    throw new FileNotFoundException("The XLSX file didn't exist on the classpath");
File file = new new File(ins.toURI());
OPCPackage pkg = OPCPackage.open(file);
XSSFWorkbook workbook = new XSSFWorkbook(pkg);

You'll want to keep the OPCPackage around until the end, so you can close it to release the file handle resources

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