Read xlsx file using POIFSFileSystem

Question

I need to unprotect a protected xlsx file.e.g Book1.xlsx Below code runs fine for the first time, Reads Book1.xlsx, decrypt it and again write it to the same filename.

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public static void unprotectXLSXSheet(String fileName, String password) {
        try{

            POIFSFileSystem fs = new POIFSFileSystem(new FileInputStream(fileName));
            EncryptionInfo info = new EncryptionInfo(fs);
            Decryptor d = Decryptor.getInstance(info);
            d.verifyPassword(password);
            InputStream is = d.getDataStream(fs);
            System.out.println(is.available());
            XSSFWorkbook wb = new XSSFWorkbook(OPCPackage.open(is));
            FileOutputStream fileOut;
            fileOut = new FileOutputStream(fileName);
            wb.write(fileOut);
             fileOut.flush();
            fileOut.close();
            }catch(FileNotFoundException ex){
                ex.printStackTrace();
            }catch(IOException ex){
                ex.printStackTrace();

But when the same code tries to access the newly created unprotected Book1.xlsx(or anyother unprotected xlsx file) it fails and showing

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Exception in thread "main" org.apache.poi.poifs.filesystem.OfficeXmlFileException: The supplied data appears to be in the Office 2007+ XML. You are calling the part of POI that deals with OLE2 Office Documents. You need to call a different part of POI to process this data (eg XSSF instead of HSSF)
    at org.apache.poi.poifs.storage.HeaderBlock.<init>(HeaderBlock.java:131)
    at org.apache.poi.poifs.storage.HeaderBlock.<init>(HeaderBlock.java:104)
    at org.apache.poi.poifs.filesystem.POIFSFileSystem.<init>(POIFSFileSystem.java:138)
    at com.wolseley.Excel.TestMainDummy.unprotectXLSXSheet(TestMainDummy.java:113)
    at com.wolseley.Excel.TestMainDummy.main(TestMainDummy.java:52)

i need help in reading xlsx file and also unlock it using password, as done above.

Answer 1

Basically the following line of code doesn't work for Office 2007+ XML documents:

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POIFSFileSystem fs = new POIFSFileSystem(new FileInputStream(fileName));

So you'll first need to check the header in the input stream whether it's supported by calling this:

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POIFSFileSystem.hasPOIFSHeader(is)

and only decrypting if the above returns true. The hasPOIFSHeader method requires an input stream that supports mark/reset, so check that as well and wrap it in a PushbackInputStream if not.

Putting it all together then becomes something like this:

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public static void unprotectXLSXSheet(String fileName, String password) throws Exception {
    InputStream is = null;
    FileOutputStream fileOut = null;

    try {
        is = new FileInputStream(fileName);
        if (!is.markSupported()) {
            is = new PushbackInputStream(is, 8);
        }

        if (POIFSFileSystem.hasPOIFSHeader(is)) {
            POIFSFileSystem fs = new POIFSFileSystem(is);
            EncryptionInfo info = new EncryptionInfo(fs);
            Decryptor d = Decryptor.getInstance(info);
            d.verifyPassword(password);
            is = d.getDataStream(fs);
        }

        System.out.println(is.available());
        XSSFWorkbook wb = new XSSFWorkbook(OPCPackage.open(is));
        fileOut = new FileOutputStream(fileName);
        wb.write(fileOut);
        fileOut.flush();
    } finally {
        if (is != null) {
            is.close();
        }
        if (fileOut != null) {
            fileOut.close();
        }
    }
}