使用Java代码将.xls转换为.xlsx格式

Question

I Need to convert xml spread sheet 2003 to .xlsx format.

in my application one link is there, if i click that link it will download the file in download folder. when i try to open that excel file it gives a message

"The file format and extension of don't match. the file could be corrupted or unsafe. unless you trust its source, don't open it. Do you want open it anyway?"

and it gives the option Yes, No , and Help.

If i click Yes, then i can see the excel sheet content. The excel sheet extension is .xls but when i go to File in Excel sheet and click on 'save as' it shows the save as type is XML spread sheet 2003.

I can do it manually save as .xlsx but every time i can't do it. Even i tried with below code

public class xls2xlsx {

 public static void main(String[] args) throws InvalidFormatException,
        IOException {

    String inpFn = "F:\\Users\\Downloads\\Report.xls"; 
    String outFn = "F:\\Users\\Downloads\\Report.xlsx"; 

    InputStream in = new BufferedInputStream(new FileInputStream(inpFn));
    try {
        Workbook wbIn = new HSSFWorkbook(in);
        File outF = new File(outFn);
        if (outF.exists())
            outF.delete();

        Workbook wbOut = new XSSFWorkbook();
        int sheetCnt = wbIn.getNumberOfSheets();
        for (int i = 0; i < sheetCnt; i++) {
            Sheet sIn = wbIn.getSheetAt(0);
            Sheet sOut = wbOut.createSheet(sIn.getSheetName());
            Iterator<Row> rowIt = sIn.rowIterator();
            while (rowIt.hasNext()) {
                Row rowIn = rowIt.next();
                Row rowOut = sOut.createRow(rowIn.getRowNum());

                Iterator<Cell> cellIt = rowIn.cellIterator();
                while (cellIt.hasNext()) {
                    Cell cellIn = cellIt.next();
                    Cell cellOut = rowOut.createCell(
                            cellIn.getColumnIndex(), cellIn.getCellType());

                    switch (cellIn.getCellType()) {
                    case Cell.CELL_TYPE_BLANK:
                        break;

                    case Cell.CELL_TYPE_BOOLEAN:
                        cellOut.setCellValue(cellIn.getBooleanCellValue());
                        break;

                    case Cell.CELL_TYPE_ERROR:
                        cellOut.setCellValue(cellIn.getErrorCellValue());
                        break;

                    case Cell.CELL_TYPE_FORMULA:
                        cellOut.setCellFormula(cellIn.getCellFormula());
                        break;

                    case Cell.CELL_TYPE_NUMERIC:
                        cellOut.setCellValue(cellIn.getNumericCellValue());
                        break;

                    case Cell.CELL_TYPE_STRING:
                        cellOut.setCellValue(cellIn.getStringCellValue());
                        break;
                    }

                    {
                        CellStyle styleIn = cellIn.getCellStyle();
                        CellStyle styleOut = cellOut.getCellStyle();
                        styleOut.setDataFormat(styleIn.getDataFormat());
                    }
                    cellOut.setCellComment(cellIn.getCellComment());

                    // HSSFCellStyle cannot be cast to XSSFCellStyle
                    // cellOut.setCellStyle(cellIn.getCellStyle());
                }
            }
        }
        OutputStream out = new BufferedOutputStream(new FileOutputStream(
                outF));
        try {
            wbOut.write(out);
        } finally {
            out.close();
        }
    } finally {
        in.close();
    }
}
}

Error

Exception in thread "main" java.io.IOException: Invalid header signature; read 0x6576206C6D783F3C, expected 0xE11AB1A1E011CFD0
    at org.apache.poi.poifs.storage.HeaderBlock.<init>(HeaderBlock.java:140)
    at org.apache.poi.poifs.storage.HeaderBlock.<init>(HeaderBlock.java:104)
    at org.apache.poi.poifs.filesystem.POIFSFileSystem.<init>(POIFSFileSystem.java:138)
    at org.apache.poi.hssf.usermodel.HSSFWorkbook.<init>(HSSFWorkbook.java:322)
    at org.apache.poi.hssf.usermodel.HSSFWorkbook.<init>(HSSFWorkbook.java:303)
    at excelSheet.xls2xlsx.main(xls2xlsx.java:42)

Answer 1

From the Excel-message I suspect that the file you try to open is already in .xslx -Format but is saved using the wrong .xls -extension.

This is supported by the poi-error-message which also appears when trying to open a .xlsx -file as a HSSFWorkbook instead of as a XSSFWorkbook - btw you seem to be using a quite old version of poi (version 2.x?), current is 3.13 and with all 3.x-versions the message yould be much more clear:

Exception in thread "main" org.apache.poi.poifs.filesystem.OfficeXmlFileException: The supplied data appears to be in the Office 2007+ XML. POI only supports OLE2 Office documents
    at org.apache.poi.poifs.storage.HeaderBlockReader.<init>(HeaderBlockReader.java:96)
    at org.apache.poi.poifs.filesystem.POIFSFileSystem.<init>(POIFSFileSystem.java:84)
    at org.apache.poi.hssf.usermodel.HSSFWorkbook.<init>(HSSFWorkbook.java:257)
    at org.apache.poi.hssf.usermodel.HSSFWorkbook.<init>(HSSFWorkbook.java:238)
    at de.nuernberger.zebra.poitest.Poitest.main(Poitest.java:10)

tl;dr there is no need to do any conversion, just make sure the file gets saved with the correct extension.