poi实现导入导出

 @Test
    public void test1() throws Exception {
        FileOutputStream fos = new FileOutputStream("C:\\Users\\suqianlong\\Desktop\\test\\b.xlsx");
        Workbook wb = new XSSFWorkbook();
        Sheet sheet = wb.createSheet();
        Row row = sheet.createRow(0);
        Cell cell = row.createCell(0);
        cell.setCellValue("姓名");
        Cell cell1 = row.createCell(1);
        cell1.setCellValue("班级");
        Cell cell2 = row.createCell(2);
        cell2.setCellValue("学生成绩表");
        Row row1 = sheet.createRow(1);
        Cell cell3 = row1.createCell(2);
        cell3.setCellValue("第一学期");
        Cell cell4 = row1.createCell(3);
        cell4.setCellValue("第二学期");
        // 合并单元格
        CellRangeAddress cra1 = new CellRangeAddress(0,1,0,0);
        CellRangeAddress cra2 = new CellRangeAddress(0,1,1,1);
        CellRangeAddress cra = new CellRangeAddress(0,0,2,3);
        sheet.addMergedRegion(cra1);
        sheet.addMergedRegion(cra2);
        sheet.addMergedRegion(cra);
        wb.write(fos);
        fos.close();
    }

 @Test
    public void test2() throws Exception {
        FileOutputStream fos = new FileOutputStream("C:\\Users\\suqianlong\\Desktop\\test\\c.xlsx");
        Workbook wb = new XSSFWorkbook();
        Sheet sheet = wb.createSheet();
        Row row = sheet.createRow(0);
        Cell cell = row.createCell(0);
        cell.setCellValue("姓名");

        Cell cell1 = row.createCell(1);
        cell1.setCellValue("班级");

        Cell cell2 = row.createCell(2);
        cell2.setCellValue("学生成绩表");

        Row row1 = sheet.createRow(1);
        Cell cell3 = row1.createCell(2);
        cell3.setCellValue("第一学期");
        Cell cell4 = row1.createCell(4);
        cell4.setCellValue("第二学期");

        Row row2 = sheet.createRow(2);
        Cell cell5 = row2.createCell(2);
        cell5.setCellValue("前半年");
        Cell cell6 = row2.createCell(3);
        cell6.setCellValue("后半年");
        Cell cell7 = row2.createCell(4);
        cell7.setCellValue("前半年");
        Cell cell8 = row2.createCell(5);
        cell8.setCellValue("后半年");
        // 合并单元格
        CellRangeAddress cra1 = new CellRangeAddress(0,2,0,0);
        CellRangeAddress cra2 = new CellRangeAddress(0,2,1,1);
        CellRangeAddress cra = new CellRangeAddress(0,0,2,5);
        CellRangeAddress cra3 = new CellRangeAddress(1,1,2,3);
        CellRangeAddress cra4 = new CellRangeAddress(1,1,4,5);
        sheet.addMergedRegion(cra1);
        sheet.addMergedRegion(cra2);
        sheet.addMergedRegion(cra);
        sheet.addMergedRegion(cra3);
        sheet.addMergedRegion(cra4);
        wb.write(fos);
        fos.close();
    }

读操作
高性能读使用 Workbook wb = new SXSSFWorkbook();

@Test
    public void testImport() throws Exception {
        String PATH = "H:\\LUA\\redis_springboot\\src\\main\\java\\com\\distributeredis\\redis_springboot\\springpoi\\明细表.xlsx";
        FileInputStream fis = new FileInputStream(PATH);
        // 获取一个工作簿
        XSSFWorkbook workbook = new XSSFWorkbook(fis);
        // 获取一个工作表
        XSSFSheet sheet = workbook.getSheetAt(0);
        // 获取第一行内容
        XSSFRow row = sheet.getRow(0);
        if(row != null) {
            // 获取所有列
            int numberOfCells = row.getPhysicalNumberOfCells();
            for (int cell = 0; cell < numberOfCells; cell++) {
                XSSFCell rowCell = row.getCell(cell);
                if(rowCell != null) {
                    String cellValue = rowCell.getStringCellValue();
                    System.out.print(cellValue + "| ");
                }
            }
        }
        System.out.println();
        // 获取表格内容
        int rows = sheet.getPhysicalNumberOfRows();
        // 从1开始，第一行是标题
        for (int rowNum = 1; rowNum < rows; rowNum++) {
            XSSFRow currentRow = sheet.getRow(rowNum);
            if(currentRow != null) {
                // 获取当前行的列数
                int cells = currentRow.getPhysicalNumberOfCells();
                for (int col = 0; col < cells; col++) {
                    // 获取当前列的值
                    XSSFCell cell = currentRow.getCell(col);
                    CellType cellType = cell.getCellType();
                    String cellValue = "";
                    switch (cellType) {
                        case STRING: // 字符串
                            cellValue = cell.getStringCellValue();
                            break;
                        case BOOLEAN:  // 布尔类型
                            cellValue = String.valueOf(cell.getBooleanCellValue());
                            break;
                        case BLANK:  // 空
                            break;
                        case NUMERIC:  // 数值类型（日期，普通数值）
                            if(DateUtil.isCellDateFormatted(cell)) {
                                Date date = cell.getDateCellValue();
                                cellValue = new DateTime(date).toString("yyyy-MM-dd");
                            }else {
                                cell.setCellType(CellType.STRING);
                                cellValue = cell.toString();
                            }
                            break;
                        case ERROR:
                            break;
                    }
                    System.out.print(cellValue+" | ");
                }
            }
            System.out.println();
        }
        workbook.close();
        fis.close();
    }