[Java知识库]springboot中poi操作合集

在项目中，有很多对excel的操作，大都数时候我们都会使用poi工具类，本文将介绍poi的一些使用方法。

1.poi导入excel，并展示数据

使用poi导入excel，解析后返回List数据到前台展示。

 /**
     * 
     * (读入excel文件，解析后返回)
     * @param file(文件类型)
     * @throws IOException
     * @return List<String[]>
     */
    public static List<String[]> readExcel(MultipartFile file)
        throws IOException {
        // 检查文件
        checkFile(file);
        // 获得Workbook工作薄对象
        Workbook workbook = getWorkBook(file);
        // 创建返回对象，把每行中的值作为一个数组，所有行作为一个集合返回
        List<String[]> list = new ArrayList<String[]>();
        if (workbook != null) {
            for (int sheetNum = 0; sheetNum < workbook.getNumberOfSheets(); sheetNum++ ) {
                // 获得当前sheet工作表
                Sheet sheet = workbook.getSheetAt(sheetNum);
                if (sheet == null) {
                    continue;
                }
                // 获得当前sheet的开始行
                int firstRowNum = sheet.getFirstRowNum();
                // 获得当前sheet的结束行
                int lastRowNum = sheet.getLastRowNum();
                // 循环除了第一行的所有行
                for (int rowNum = firstRowNum + 1; rowNum <= lastRowNum; rowNum++ ) {
                    // 获得当前行
                    Row row = sheet.getRow(rowNum);
                    if (row == null) {
                        continue;
                    }
                    // 获得当前行的开始列
                    int firstCellNum = row.getFirstCellNum();
                    // 获得当前行的列数
                    int lastCellNum = row.getLastCellNum();
                    String[] cells = new String[row.getLastCellNum()];
                    // 循环当前行
                    for (int cellNum = firstCellNum; cellNum < lastCellNum; cellNum++ ) {                    
                        Cell cell=row.getCell(cellNum, Row.MissingCellPolicy.RETURN_BLANK_AS_NULL);
                        cells[cellNum] = getCellValue(cell);
                    }
                    list.add(cells);
                }
            }
        }
        return list;
    }
 
    /**
     * 
     * (判断文件)
     * @param file
     * @throws IOException
     * @return void
     */
    public static void checkFile(MultipartFile file)
        throws IOException {
        // 判断文件是否存在
        if (null == file) {
            throw new FileNotFoundException("文件不存在！");
        }
        // 获得文件名
        String fileName = file.getOriginalFilename();
        // 判断文件是否是excel文件
        if (!fileName.endsWith(XLS_TYPE) && !fileName.endsWith(XLSX_TYPE)) {
            throw new IOException(fileName + "不是excel文件");
        }
    }
 
    public static String getCellValue(Cell cell) {
        String cellValue = "";
        if (cell == null) {
            return cellValue;
        }
        // 把数字当成String来读，避免出现1读成1.0的情况
        if (cell.getCellType() == Cell.CELL_TYPE_NUMERIC) {
            cell.setCellType(Cell.CELL_TYPE_STRING);
        }
        // 判断数据的类型
        switch (cell.getCellType()) {
            // 数字
            case Cell.CELL_TYPE_NUMERIC:
                cellValue = String.valueOf(cell.getNumericCellValue());
                break;
            // 字符串
            case Cell.CELL_TYPE_STRING:
                cellValue = String.valueOf(cell.getStringCellValue());
                break;
            // Boolean
            case Cell.CELL_TYPE_BOOLEAN:
                cellValue = String.valueOf(cell.getBooleanCellValue());
                break;
            // 公式
            case Cell.CELL_TYPE_FORMULA:
                cellValue = String.valueOf(cell.getCellFormula());
                break;
            // 空值
            case Cell.CELL_TYPE_BLANK:
                cellValue = "";
                break;
            // 故障
            case Cell.CELL_TYPE_ERROR:
                cellValue = "非法字符";
                break;
            default:
                cellValue = "未知类型";
                break;
        }
        return cellValue;
    }
 
    /**
     * 
     * (getWorkBook:(创建WorkBook对象))
     * @param file
     * @return
     * @return Workbook
     */
    public static Workbook getWorkBook(MultipartFile file) {
        // 获得文件名
        String fileName = file.getOriginalFilename();
        // 创建Workbook工作薄对象，表示整个excel
        Workbook workbook = null;
        try {
            // 获取excel文件的io流
            InputStream is = file.getInputStream();
            // 根据文件后缀名不同(xls和xlsx)获得不同的Workbook实现类对象
            if (fileName.endsWith(XLS_TYPE)) {
                // 2003
                workbook = new HSSFWorkbook(is);
            }
            else if (fileName.endsWith(XLSX_TYPE)) {
                // 2007
                workbook = new XSSFWorkbook(is);
            }
        }
        catch (IOException e) {
            e.printStackTrace();
        }
        return workbook;
    }

2.poi导出excel并以web下载方式保存excel

将数据库中的数据组装成excel并导出，并在web下载栏中直接下载。

/**
     * 人员导出
     *
     * @param sysSysUserVO
     * @throws IOException
     */
    @PostMapping("/exportUser")
    @ApiOperation(value = "导出人员excel", notes = "导出人员excel")
    public void
        exportUser(@ApiParam(name = "人员id", value = "人员id", required = false) @RequestBody List<SysUserVO> sysSysUserVO)
            throws IOException {
        List<SysUserVO> middleList = new ArrayList<>();
        // 查询用户详细信息
        for (SysUserVO sysUserVO : sysSysUserVO) {
            List<SysUserVO> resultListSysUser = sysUserService.querySysUserAll(sysUserVO);
            userInfoUtil.completionInformation(resultListSysUser.get(0));
            middleList.add(resultListSysUser.get(0));
        }
        // excle格式
        String[] headers = {"用户名", "姓名", "密码", "启动状态", "岗位", "角色", "所属部门", "手机", "邮箱", "身份证号"};
        HSSFWorkbook workbook = new HSSFWorkbook();
        HSSFSheet sheet = workbook.createSheet();
        // 设置列宽
        sheet.setDefaultColumnWidth((short)18);
        HSSFRow row = sheet.createRow(0);
        for (short i = 0; i < headers.length; i++) {
            // 创建单元格，每行多少数据就创建多少个单元格
            HSSFCell cell = row.createCell(i);
            HSSFRichTextString text = new HSSFRichTextString(headers[i]);
            // 给单元格设置内容
            cell.setCellValue(text);
        }
        for (int j = 0; j < middleList.size(); j++) {
            SysUserVO export = middleList.get(j);
            // 从第二行开始填充数据
            row = sheet.createRow(j + 1);
            List<String> datas = new ArrayList<>();
            String userName = export.getUsername();
            String trueName = export.getTureName();
            String password = export.getPassword();
            String status = String.valueOf(export.getIsEnabled());
            String postName = export.getPostName();
            String roleName = export.getRoleName();
            String organName = export.getOrganizationName();
            String phone = export.getMobile();
            String email = export.getEmail();
            String identityCard = export.getIdentityCard();
            datas.add(userName);
            datas.add(trueName);
            datas.add(password);
            datas.add(status);
            datas.add(postName);
            datas.add(roleName);
            datas.add(organName);
            datas.add(phone);
            datas.add(email);
            datas.add(identityCard);
            for (int k = 0; k < datas.size(); k++) {
                String string = datas.get(k);
                HSSFCell cell = row.createCell(k);
                HSSFRichTextString richString = new HSSFRichTextString(string);
                HSSFFont font3 = workbook.createFont();
                // 定义Excel数据颜色，这里设置为蓝色
                font3.setColor(HSSFColor.BLUE.index);
                richString.applyFont(font3);
                cell.setCellValue(richString);
            }
        }
        String fileName = "人员导出.xls";
        // 导出
        HttpServletResponse response =
            ((ServletRequestAttributes)RequestContextHolder.getRequestAttributes()).getResponse();
        RequestAttributes requsetAttributes = RequestContextHolder.currentRequestAttributes();
        HttpServletRequest request = ((ServletRequestAttributes)requsetAttributes).getRequest();
        // 获得浏览器代理信息
        final String userAgent = request.getHeader("USER-AGENT");
        // 判断浏览器代理并分别设置响应给浏览器的编码格式
        if (StringUtils.contains(userAgent, "MSIE") || StringUtils.contains(userAgent, "Trident")) {
            // IE浏览器
            fileName = URLEncoder.encode(fileName, "UTF-8");
        } else if (StringUtils.contains(userAgent, "Mozilla")) {
            // google,火狐浏览器
            fileName = new String(fileName.getBytes("UTF-8"), "ISO8859-1");
        } else {
            // 其他浏览器
            fileName = URLEncoder.encode(fileName, "UTF-8");// 其他浏览器
        }
        // 设置HTTP响应头
        response.reset();
        // 重置 如果不在页面上显示而是下载下来 则放开注释
        response.setContentType("application/octet-stream");
        response.addHeader("Content-Disposition", "attachment;filename=\"" + fileName + "\"");
        OutputStream os = response.getOutputStream();
        workbook.write(os);
        os.close();
    }

3.poi导出并以流方式保存excel

将数据库中的数据组装成excel并导出，并以数据流方式存在指定的路径。

public class BarcodeExportlFlow implements IBarcodeExport {
 
    @Autowired
    BarcodeManageBatchSerivce barcodeManageBatchSerivce;
 
    @Override
    public OutputStream exportData() throws IOException {
 
        //查询批次码
        BarcodeBatchManageBo input = new BarcodeBatchManageBo();
        List<BarcodeBatchManageBo> middleList = barcodeManageBatchSerivce.selectBatch(input);
        String[] headers = {"id", "条码批次码", "激活状态", "有效状态", "导入人", "导入时间", "激活人", "激活时间", "作废人", "作废时间", "本批次条数"};
        HSSFWorkbook workbook = new HSSFWorkbook();
        HSSFSheet sheet = workbook.createSheet();
        //设置列宽
        sheet.setDefaultColumnWidth((short) 18);
        HSSFRow row = sheet.createRow(0);
        for (short i = 0; i < headers.length; i++) {
            //创建单元格，每行多少数据就创建多少个单元格
            HSSFCell cell = row.createCell(i);
            HSSFRichTextString text = new HSSFRichTextString(headers[i]);
            //给单元格设置内容
            cell.setCellValue(text);
        }
 
        for (int j = 0; j < middleList.size(); j++) {
            BarcodeBatchManageBo export = middleList.get(j);
            //从第二行开始填充数据
            row = sheet.createRow(j + 1);
            List<String> datas = new ArrayList<>();
            String id = export.getId().toString();
            String batchCode = export.getBatchCode();
            String activationStatus = export.getActivationStatus();
            String effectiveStatus = export.getEffectiveStatus();
            datas.add(id);
            datas.add(batchCode);
            datas.add(activationStatus);
            datas.add(effectiveStatus);
            for (int k = 0; k < datas.size(); k++) {
                String string = datas.get(k);
                HSSFCell cell = row.createCell(k);
                HSSFRichTextString richString = new HSSFRichTextString(string);
                HSSFFont font3 = workbook.createFont();
                //定义Excel数据颜色，这里设置为蓝色
                font3.setColor(HSSFColor.BLUE.index);
                richString.applyFont(font3);
                cell.setCellValue(richString);
            }
        }
        FileOutputStream fos = new FileOutputStream("D:/wb.xls");
        workbook.write(fos);
        fos.close();
        return null;
    }
}