springboot 通过 poi 导出 excel

Maven 引入依赖

<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi</artifactId>
    <version>RELEASE</version>
</dependency>
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi-ooxml</artifactId>
    <version>RELEASE</version>
</dependency>

导出 excel

导出 excel 比较重要的 api 有以下几个，其他的并无难点

• 创建一个 excel 文件工作薄；（HSSFWorkbook workbook = new HSSFWorkbook()）
• 创建一张表；HSSFSheet sheet = workbook.createSheet("统计表")
• 创建一行；HSSFRow row = sheet.createRow(0)
• 填充一列数据; row.createCell(0).setCellValue("数据")
• 设置一个单元格样式；cell.setCellStyle(style)

注意！！！ 如果文件没有提示下载 则不代表生成 EXCEL 失败 文件会在项目 根目录 中自动生成！！

    public HSSFWorkbook createExcel(SearchParams params) {
        // 第一步创建workbook
        HSSFWorkbook wb = new HSSFWorkbook();

        // 第二步创建sheet
        HSSFSheet sheet = wb.createSheet("列表");
        // 设置列宽，setColumnWidth的第二个参数要乘以256，这个参数的单位是1/256个字符宽度
        sheet.setColumnWidth(0, 256 * 20);
        sheet.setColumnWidth(1, 256 * 20);
        sheet.setColumnWidth(2, 256 * 20);
        sheet.setColumnWidth(3, 256 * 10);
        sheet.setColumnWidth(4, 256 * 20);
        sheet.setColumnWidth(5, 256 * 20);

        // 第三步创建行row:添加表头0行
        HSSFRow row = sheet.createRow(0);
        HSSFCellStyle style = wb.createCellStyle();

        // 设置为居中加粗
        // HSSFCellStyle style = workbook.createCellStyle();
        // HSSFFont font = workbook.createFont();
        // font.setBold(true);
        // style.setAlignment(HSSFCellStyle.ALIGN_CENTER);
        // style.setFont(font);

        // 第四步创建单元格
        int cellColumn = 0;
        // 第一个单元格
        HSSFCell cell = row.createCell(cellColumn++);
        cell.setCellValue("ID");
        cell.setCellStyle(style);

        // 第二个单元格
        cell = row.createCell(cellColumn++);
        cell.setCellValue("用户");
        cell.setCellStyle(style);

        // 第三个单元格
        cell = row.createCell(cellColumn++);
        cell.setCellValue("时间");
        cell.setCellStyle(style);

        // 第四个单元格
        cell = row.createCell(cellColumn++);
        cell.setCellValue("符号");
        cell.setCellStyle(style);

        // 第五个单元格
        cell = row.createCell(cellColumn++);
        cell.setCellValue("数量");
        cell.setCellStyle(style);

        AtomicInteger index = new AtomicInteger();
        // 自增跳过表头
        index.incrementAndGet();
        fillData(params, index, sheet);

        return wb;
    }

     private void fillData(SearchParams params, AtomicInteger index, HSSFSheet sheet) {
        // 自定义分页查找数据
        PageInfo<SearchListForm> pageInfo = this.service.getDataBySearch(params);
        List<SearchListForm> searchList = pageInfo.getList(); 
        Optional.ofNullable(searchList).ifPresent(list -> list.stream().forEach(v -> {
            HSSFRow row = sheet.createRow(index.getAndIncrement());

            // 设置日期格式
            // HSSFCellStyle style = workbook.createCellStyle();
            // style.setDataFormat(HSSFDataFormat.getBuiltinFormat("m/d/yy h:mm"));

            // HSSFCell cell = row.createCell(3);
            // cell.setCellValue(user.getCreate_time());
            // cell.setCellStyle(style);

            int cellColumn = 0;
            row.createCell(cellColumn++).setCellValue(v.getId());
            row.createCell(cellColumn++).setCellValue(v.getUsername());
            row.createCell(cellColumn++).setCellValue(DateFormatUtils.format(v.getCreatetime(), "MM/dd/yyyy HH:mm:ss"));
            row.createCell(cellColumn++).setCellValue(v.getSymbol());
            row.createCell(cellColumn++).setCellValue(v.getQuantity().setScale(8, RoundingMode.HALF_DOWN).stripTrailingZeros().toPlainString());
        }));

        // 循环获取数据
        if (pageInfo.isHasNextPage()) {
            params.setPage(pageInfo.getNextPage());
            fillData(params, index, sheet);
        }
    }

@GetMapping(value = "downloadExcel")
    public void (
            @RequestBody @ApiParam(required = false, name = "SearchParams", value = "参数") SearchParams params,
            HttpServletResponse response
    ) {
        params.setPage(1);
        params.setRows(1000);
        String fileName = LocalDate.now().format(DateTimeFormatter.ofPattern("yyyyMMdd")) + "_ExcelData" + ".xls";
        response.setContentType("application/octet-stream");
        response.setHeader("Pragma", "no-cache");
        response.setHeader("Cache-Control", "no-cache");
        response.setDateHeader("Expires", 0);
        response.setHeader("Content-disposition", "attachment;filename=" + fileName);
        OutputStream outputStream = null;
        HSSFWorkbook wb = null;
        try {
            outputStream = response.getOutputStream();
            // 刷新缓冲
            response.flushBuffer();
            wb = createExcel(params);
            wb.write(outputStream);
        } catch (IOException e) {
            logger.info("IOException {}", e);
        } finally {
            IOUtils.closeQuietly(wb);
            IOUtils.closeQuietly(outputStream);
        }
    }

    // 生成excel文件
    protected void buildExcelFile(String filename,HSSFWorkbook workbook) throws Exception{
        FileOutputStream fos = new FileOutputStream(filename);
        workbook.write(fos);
        fos.flush();
        fos.close();
    }

    // 浏览器下载excel
    protected void buildExcelDocument(String filename,HSSFWorkbook workbook,HttpServletResponse response) throws Exception{
        response.setContentType("application/vnd.ms-excel");
        response.setHeader("Content-Disposition", "attachment;filename="+URLEncoder.encode(filename, "utf-8"));
        OutputStream outputStream = response.getOutputStream();
        workbook.write(outputStream);
        outputStream.flush();
        outputStream.close();
    }

通过 swagger 直接下载可能会出现乱码