java - InputStream 如何转换为 apache.poi Workbook？

Question

我需要文件excel来转换Workbook（apache poi）。我得到InputStream：

InputStream in = getInputStream(); // from user file.xls
if(in != null){
    HSSFWorkbook hssfWorkbook = new  HSSFWorkbook(in); //exception
}

但接下来我得到了例外：

org.apache.poi.poifs.filesystem.NotOLE2FileException：无效的标头签名；读取 0x0005060000100809，预期为 0xE11AB1A1E011CFD0 - 您的文件似乎不是有效的 OLE2 文档

我从文件中获得的 InputStream 是构建 Apachi Poi

和问题NotOLE2FileException: Invalid header signature; 读取 0x0000000000000000，预期 0xE11AB1A1E011CFD0 对我不起作用

我使用 Vaadin 框架。

MultiFileMemoryBuffer buffer = new MultiFileMemoryBuffer();

Upload upload = new Upload(buffer);
upload.setAcceptedFileTypes("application/vnd.ms-excel");
upload.setMaxFiles(1);
upload.setSizeFull();
upload.addSucceededListener((event) -> {

        name = event.getFileName();

        try (InputStream inputStream = buffer.getInputStream(name) // getInputStream
             ) {
                Workbook workbook = WorkbookFactory.create(inputStream);

            } catch (IOException e) {
                e.printStackTrace();
            }
        });
}