import org.apache.poi.openxml4j.exceptions.NotOfficeXmlFileException; //导入依赖的package包/类
/**
    Uses Apache POI to extract information from xlsx file into a 2D array.
    Here is where we got our starter code: http://www.mkyong.com/java/apache-poi-reading-and-writing-excel-file-in-java/
    Look at example number 4, Apache POI library – Reading an Excel file.

    This file originally just printed data, that is why there are several commented out lines in the code.
    We have repurposed this method to put all data into a 2D String array and return it.
 */
public String[][] extractFromXLSX(InputStream excelFile) throws NotOfficeXmlFileException {
    try {
        Workbook workbook = new XSSFWorkbook(excelFile);
        Sheet datatypeSheet = workbook.getSheetAt(0);

        String[][] cellValues = new String[datatypeSheet.getLastRowNum() + 1]
                [max(max(datatypeSheet.getRow(1).getLastCellNum(), datatypeSheet.getRow(2).getLastCellNum()),
                datatypeSheet.getRow(3).getLastCellNum())];

        for (Row currentRow : datatypeSheet) {
            //cellValues[currentRow.getRowNum()] = new String[currentRow.getLastCellNum()];

            for (Cell currentCell : currentRow) {

                //getCellTypeEnum shown as deprecated for version 3.15
                //getCellTypeEnum ill be renamed to getCellType starting from version 4.0
                if (currentCell.getCellTypeEnum() == CellType.STRING) {
                    cellValues[currentCell.getRowIndex()][currentCell.getColumnIndex()] = currentCell.getStringCellValue();
                } else if (currentCell.getCellTypeEnum() == CellType.NUMERIC) {
                    cellValues[currentCell.getRowIndex()][currentCell.getColumnIndex()] =
                            Integer.toString((int) Math.round(currentCell.getNumericCellValue()));
                }

            }

        }
        return cellValues;
    } catch (IOException e) {
        System.out.println("EVERYTHING BLEW UP STOP STOP STOP");
        e.printStackTrace();
        return null; //TODO: this should not return null. This should continue.
    }

}
 

import org.apache.poi.openxml4j.exceptions.NotOfficeXmlFileException; //导入依赖的package包/类
private List<String> readAsXLS(String path) {
    try {
        XLS2CSV xls2csv = new XLS2CSV(path, -1);
        return xls2csv.process();
    } catch (Exception e) {
        if (e instanceof NotOLE2FileException || e instanceof NotOfficeXmlFileException || e instanceof OfficeXmlFileException) {
            throw new ExcelOperBaseException("请选择正确格式excel文件");
        }
        if (e instanceof IOException) {
            throw new ExcelOperBaseException("文件读取失败");
        }
        throw new RuntimeException(e);
    }
}
 

import org.apache.poi.openxml4j.exceptions.NotOfficeXmlFileException; //导入依赖的package包/类
@Test(expected = NotOfficeXmlFileException.class)
public void testEmptyDoc() throws InvalidFormatException, IOException {
    final File file = new File("resources/document/empty/empty-template.docx");
    assertTrue(file.exists());
    try (FileInputStream is = new FileInputStream(file);
            OPCPackage oPackage = OPCPackage.open(is);
            XWPFDocument document = new XWPFDocument(oPackage);) {
        TokenIterator iterator = new TokenIterator(document);

        assertTrue(!iterator.hasNext());
    }
}
 

import org.apache.poi.openxml4j.exceptions.NotOfficeXmlFileException; //导入依赖的package包/类
private List<String> readAsXLS(String path){
	try {				
		XLS2CSV xls2csv = new XLS2CSV(path, -1);
		return xls2csv.process();
	} catch (Exception e) {
		if(e instanceof NotOLE2FileException || e instanceof NotOfficeXmlFileException || e instanceof OfficeXmlFileException){
			throw new ExcelOperBaseException("请选择正确格式excel文件");
		}
		if(e instanceof IOException){
			throw new ExcelOperBaseException("文件读取失败");
		}
		throw new RuntimeException(e);
	}
}
 

import org.apache.poi.openxml4j.exceptions.NotOfficeXmlFileException; //导入依赖的package包/类
private Workbook openFileAsWorkBook(MultipartFile file, FileParserMessage<DataFileColumn> msg) throws IOException {
    try {
        String fileName = file.getOriginalFilename();
        if (".xlsx".equals(fileName.substring(fileName.lastIndexOf(".")))) {
            return new XSSFWorkbook(file.getInputStream());
        }
        if (".xls".equals(fileName.substring(fileName.lastIndexOf(".")))) {
            return new HSSFWorkbook(file.getInputStream());
        }
        throw new NotOfficeXmlFileException("Not recognized type");
    } catch (NotOfficeXmlFileException e) {
        msg.addFileParseError(new FileParseError(0, "Invalid file type"));
        throw new IOException();
    }
}
 

import org.apache.poi.openxml4j.exceptions.NotOfficeXmlFileException; //导入依赖的package包/类
/**
 * Reads a list of POJOs from the given excel file.
 *
 * @param file Excel file to read from
 * @param sheetName The sheet to extract from in the workbook
 * @param reader The reader class to use to load the file from the sheet
 */
public static void process(File file, String sheetName, ZeroCellReader reader) {
    try (FileInputStream fis = new FileInputStream(file);
         OPCPackage opcPackage = OPCPackage.open(fis)) {

        DataFormatter dataFormatter = new DataFormatter();
        ReadOnlySharedStringsTable strings = new ReadOnlySharedStringsTable(opcPackage);
        XSSFReader xssfReader = new XSSFReader(opcPackage);
        StylesTable stylesTable = xssfReader.getStylesTable();
        InputStream sheetInputStream = null;
        XSSFReader.SheetIterator sheets = (XSSFReader.SheetIterator) xssfReader.getSheetsData();
        while (sheets.hasNext()) {
            sheetInputStream = sheets.next();
            if (sheets.getSheetName().equalsIgnoreCase(sheetName)) {
                break;
            } else {
                sheetInputStream = null;
            }
        }

        if (Objects.isNull(sheetInputStream)) {
            throw new SheetNotFoundException(sheetName);
        }

        XMLReader xmlReader = SAXHelper.newXMLReader();
        xmlReader.setContentHandler(new XSSFSheetXMLHandler(stylesTable, strings, reader, dataFormatter, false));
        xmlReader.parse(new InputSource(sheetInputStream));
        sheetInputStream.close();
        xmlReader = null;
        sheetInputStream = null;
        stylesTable = null;
        strings = null;
        xssfReader = null;
    } catch(org.apache.poi.openxml4j.exceptions.InvalidFormatException | NotOfficeXmlFileException ife) {
        throw new ZeroCellException("Cannot load file. The file must be an Excel 2007+ Workbook (.xlsx)");
    } catch(SheetNotFoundException ex) {
        throw new ZeroCellException(ex.getMessage());
    } catch (ZeroCellException ze) {
        throw ze; // Rethrow the Exception
    } catch (Exception e) {
        throw new ZeroCellException("Failed to process file", e);
    }
}