java中excel文件下载

1、System.getProperty(user.dir) 获取的是启动项目的容器位置

2、 Files.copy(sourceFile.toPath(), destinationFile.toPath(), StandardCopyOption.REPLACE_EXISTING);

• StandardCopyOption.REPLACE_EXISTING 来忽略文件已经存在的异常，如果存在就去覆盖掉它
• StandardCopyOption.COPY_ATTRIBUTES copy文件的属性，最近修改时间，最近访问时间等信息，不仅copy文件的内容，连文件附带的属性一并复制
   

    //获得要下载的excel的模板、其中mb.xlsx是模板String sourceFilePath = System.getProperty("user.dir") + File.separator + "mb.xlsx";//获得用户的当前工作目录String currentPath = System.getProperty("user.dir");//创建要生成的excel的路径String fileName1 = "mb" + System.currentTimeMillis();String destinationFilePath = currentPath + File.separator + fileName1 + ".xlsx";// 创建源文件和目标文件对象File sourceFile = new File(sourceFilePath);File destinationFile = new File(destinationFilePath);try {// 复制文件Files.copy(sourceFile.toPath(), destinationFile.toPath(), StandardCopyOption.REPLACE_EXISTING);System.out.println("文件复制成功！");} catch (IOException e) {e.printStackTrace();}//填充数据exportRawData(list, 1, destinationFilePath);String fileName = "分析-" + s + "月.xlsx";File file = new File(destinationFilePath); if (file.exists()) {String mimeType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";response.setContentType(mimeType);response.setContentLength((int) file.length());response.setCharacterEncoding("UTF-8");response.setHeader("content-Type", "application/vnd.ms-excel");response.setHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(fileName, "UTF-8"));try (BufferedInputStream inStream = new BufferedInputStream(new FileInputStream(file));BufferedOutputStream outStream = new BufferedOutputStream(response.getOutputStream())) {byte[] buffer = new byte[4096];int bytesRead;while ((bytesRead = inStream.read(buffer)) != -1) {outStream.write(buffer, 0, bytesRead);}}} else {response.sendError(HttpServletResponse.SC_NOT_FOUND);}Files.delete(Paths.get(destinationFilePath));
}

 填充数据的代码：

    boolean exportRawData(List<ImpactIndexTable> list, Integer type, String filePath) {String sheetName ="原始数据";// 要填充数据的起始行数int rowNum = 4;// 要填充数据的起始列数int colNum = 0;int rowTotal = 18;try (FileInputStream fis = new FileInputStream(filePath);Workbook workbook = new XSSFWorkbook(fis)) {Sheet sheet = workbook.getSheet(sheetName);if (sheet == null) {// 如果指定的工作表不存在，可以在这里进行处理log.info("指定的工作表不存在！");}for (int i = 0; i < list.size(); i++) {// 创建并设置单元格样式CellStyle style = workbook.createCellStyle();style.setAlignment(HorizontalAlignment.CENTER);style.setVerticalAlignment(VerticalAlignment.CENTER);SXSSFWorkbook wb = new SXSSFWorkbook(-1);// 获取要填充的行Row row = sheet.getRow(rowNum + i);if (row == null) {row = sheet.createRow(rowNum + i);}for (int n = 0; n < rowTotal; n++) {Cell cell = row.createCell(colNum + n);switch (n) {case 0:cell.setCellValue(list.get(i).getProjectName());cell.setCellStyle(style);break;case 1:cell.setCellValue(list.get(i).getHw());cell.setCellStyle(style);break;//后续按照需要填充数据default:}}}// 保存修改后的Excel文件try (FileOutputStream fos = new FileOutputStream(filePath)) {workbook.write(fos);log.info("数据导出成功:{}", type);return true;}} catch (Exception e) {log.error("导出错误:{}", e);}return false;}