POI无法打开工作簿以打开.xls文件，并且日食会引发异常

Question

When I try to open a .xlsx file in POI, I get an exception:

  java.lang.IllegalArgumentException: The supplied POIFSFileSystem does not contain a BIFF8      'Workbook' entry. Is it really an excel file? 
        at org.apache.poi.hssf.usermodel.HSSFWorkbook.getWorkbookDirEntryName(HSSFWorkbook.java:223)
        at org.apache.poi.hssf.usermodel.HSSFWorkbook.<init>(HSSFWorkbook.java:245)
        at org.apache.poi.hssf.usermodel.HSSFWorkbook.<init>(HSSFWorkbook.java:188)
        at org.apache.poi.hssf.usermodel.HSSFWorkbook.<init>(HSSFWorkbook.java:170)

InputStream input = new BufferedInputStream( new FileInputStream(fileName));

                            POIFSFileSystem file = new POIFSFileSystem( input );
                            //Create Workbook instance holding reference to .xls file
                            HSSFWorkbook wb = new HSSFWorkbook(file);

                            //Get first/desired sheet from the workbook
                            HSSFSheet sheet = wb.getSheetAt(0);

                        //Iterate through each rows one by one
                        Iterator<Row> rowIterator = sheet.iterator();

just trying to read the data that .xls file contain but cannot open it !

Answer 1

Don't create an HSSFWorkbook on a .xlsx file. An HSSFWorkbook represents an .xls file, and an XSSFWorkbook represents an .xlsx file.

In fact, usually your code doesn't even need to know which it's working with. Create your Workbook with WorkbookFactory , as this example from the Busy Developer's Guide shows:

// Use a file
Workbook wb = WorkbookFactory.create(new File("MyExcel.xls"));

// Use an InputStream, needs more memory
Workbook wb = WorkbookFactory.create(new FileInputStream("MyExcel.xlsx"));

If you must, you can create an XSSFWorkbook directly:

XSSFWorkbook wb = new XSSFWorkbook(inputStream);  // You can use a FileInputStream

or with an OPCPackage .

OPCPackage pkg = OPCPackage.open(myInputStream);
XSSFWorkbook wb = new XSSFWorkbook(pkg);