Spring MVC, Excel file download, corrupts file

Question

I'am working on an excel export functionality in one of my webapps. I set up a little test case and got the download working, but the xlsx file is corrupted and don't know what else I could try. If I write the excel to file it opens without problem, so the error must occure when downloading.

The setup:

spring-mvc 3.2.7 poi 3.10.1 Tomcat 8.0

Controller method:

@RequestMapping(value = "/download", method = RequestMethod.GET)
public ModelAndView downloadExcel() {
    // create some sample data
    List<Book> listBooks = new ArrayList<Book>();
    listBooks.add(new Book("Effective Java", "Joshua Bloch", "0321356683",
            "May 28, 2008", 38.11F));
    listBooks.add(new Book("Head First Java", "Kathy Sierra & Bert Bates",
            "0596009208", "February 9, 2005", 30.80F));
    listBooks.add(new Book("Java Generics and Collections",
            "Philip Wadler", "0596527756", "Oct 24, 2006", 29.52F));
    listBooks.add(new Book("Thinking in Java", "Bruce Eckel", "0596527756",
            "February 20, 2006", 43.97F));
    listBooks.add(new Book("Spring in Action", "Craig Walls", "1935182358",
            "June 29, 2011", 31.98F));

    // return a view which will be resolved by an excel view resolver
    return new ModelAndView(new ExcelBuilder(listBooks));
}

Abstract Custom View:

public abstract class AbstractPOIExcelView extends AbstractView {

private static final String CONTENT_TYPE_XLSX = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";

public AbstractPOIExcelView() {
}

@Override
protected boolean generatesDownloadContent() {
    return true;
}

@Override
protected final void renderMergedOutputModel(Map<String, Object> model, HttpServletRequest request,
        HttpServletResponse response) throws Exception {
    XSSFWorkbook workbook = new XSSFWorkbook();
    buildExcelDocument(model, workbook, request, response);
    ByteArrayOutputStream baos = createTemporaryOutputStream();
    response.setHeader("Content-Disposition", "attachment;filename=filename.xlsx");
    response.setContentType(CONTENT_TYPE_XLSX);
    workbook.write(baos);

    writeToResponse(response, baos);

}

protected abstract void buildExcelDocument(Map<String, Object> model, XSSFWorkbook workbook,
        HttpServletRequest request, HttpServletResponse response) throws Exception;

}

ExcelBuilder:

public class ExcelBuilder extends AbstractPOIExcelView {

private List<Book> listBooks;

public ExcelBuilder(List<Book> books) {
    this.listBooks = books;
}

@Override
protected void buildExcelDocument(Map<String, Object> model, XSSFWorkbook workbook, HttpServletRequest request, HttpServletResponse response) throws Exception {
    Sheet sheet = workbook.createSheet("Java Books");
    sheet.setDefaultColumnWidth(30);

    Row header = sheet.createRow(0);
    header.createCell(0).setCellValue("Book Title");
    header.createCell(1).setCellValue("Author");
    header.createCell(2).setCellValue("ISBN");
    header.createCell(3).setCellValue("Published Date");
    header.createCell(4).setCellValue("Price");

    // create data rows
    int rowCount = 1;

    for (Book aBook : listBooks) {
        Row aRow = sheet.createRow(rowCount++);
        aRow.createCell(0).setCellValue(aBook.getTitle());
        aRow.createCell(1).setCellValue(aBook.getAuthor());
        aRow.createCell(2).setCellValue(aBook.getIsbn());
        aRow.createCell(3).setCellValue(aBook.getPublishedDate());
        aRow.createCell(4).setCellValue(aBook.getPrice());
    }
}
}

Response Header:

 Cache-Control:private, must-revalidate
 Content-Disposition:attachment;filename="filename.xlsx"
 Content-Language:de-DE
 Content-Length:3778
 Content-Type:application/vnd.openxmlformats-officedocument.spreadsheetml.sheet;charset=ISO-8859-1
 Date:Wed, 19 Nov 2014 12:52:05 GMT
 Expires:Thu, 01 Jan 1970 00:00:00 GMT
 Pragma:private
 Set-Cookie:JSESSIONID=07F50FF2B63D4003311DE222782C4E89; Path=/abc/; HttpOnly
 X-Content-Type-Options:nosniff
 X-Frame-Options:DENY
 X-XSS-Protection:1; mode=block

It confuses me that the charset will be set, when this is binary data. Could that be the problem?

Answer 1

Don't return ModelAndView but just write the excel file to the response's outputStream

@RequestMapping(value = "/download", method = RequestMethod.GET)
@ResponseBody
public Object downloadExcel(HttpServletResponse response) {
        response.setContentType("application/vnd.ms-excel");
        response.setHeader("Content-disposition",
                "attachment; filename=" + theFileNameString + ".xls");
        try {
            generateExcel(response.getOutputStream());
        } catch (IOException e) {
            System.out.println("ERROR: " + e);
        }
    return null;
}

Check all the streams flushed/closed