SpringBoot实现接口提供下载文件

public ResponseEntity export(File file) {

    if (file == null) {
        return null;
    }
    HttpHeaders headers = new HttpHeaders();
    headers.add("Cache-Control", "no-cache, no-store, must-revalidate");
    headers.add("Content-Disposition", "attachment; filename=" + System.currentTimeMillis() + ".xls");
    headers.add("Pragma", "no-cache");
    headers.add("Expires", "0");
    headers.add("Last-Modified", new Date().toString());
    headers.add("ETag", String.valueOf(System.currentTimeMillis()));

    return ResponseEntity
            .ok()
            .headers(headers)
            .contentLength(file.length())
            .contentType(MediaType.parseMediaType("application/octet-stream"))
            .body(new FileSystemResource(file));
}

@RequestMapping("/getExcel")

public ResponseEntity<FileSystemResource> getUserExcel(@RequestParam(required=false) String fromId,@RequestParam(required=false) String type) throws Throwable {
    logger.debug("获取用户excel参数：fromId=",fromId);
    Children children = depthFindParentId(fromId, new Children());
    File file = getExcelFile(children);
    return export(file);
}

亲测可用

加一个递归函数：

public Children depthFindParentId( String parentId,Children child) throws Throwable {

    Children children = _ucApi.findChildren( parentId, true, true, true, null);
    child.getUsers().addAll(children.getUsers()); //用户
    child.getDepartments().addAll(children.getDepartments());//部门
    if (children.getDepartments().size() > 0) {
        for (Department dep : children.getDepartments()) {
            depthFindParentId(dep.getId(),child);
        }
    }
    return child;
}

 文件不落地

@RequestMapping("/excelExample")

public ResponseEntity<byte[]> excel() throws IOException {
    // 创建工作薄
    HSSFWorkbook workbook = new HSSFWorkbook();
    // 创建用户工作表
    HSSFSheet sheet = workbook.createSheet("用户列表");
    HSSFRow rows = sheet.createRow(0);
    rows.createCell(0).setCellValue("用户ID");
    rows.createCell(1).setCellValue("姓名");
    rows.createCell(2).setCellValue("手机号");
    rows = sheet.createRow(0);
    rows.createCell(0).setCellValue("栏目ID");
    rows.createCell(1).setCellValue("栏目名称");

    sheet = workbook.createSheet("部门列表");
    rows = sheet.createRow(0);
    rows.createCell(0).setCellValue("部门ID");
    rows.createCell(1).setCellValue("部门名称");

    ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
    try {
        workbook.write(outputStream);
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        outputStream.close();
    }
    HttpHeaders httpHeaders = new HttpHeaders();
    String fileName = new String("用户部门.xls".getBytes("UTF-8"), "iso-8859-1");
    httpHeaders.setContentDispositionFormData("attachment", fileName);
    httpHeaders.setContentType(MediaType.APPLICATION_OCTET_STREAM);
    ResponseEntity<byte[]> filebyte = new ResponseEntity<byte[]>(outputStream.toByteArray(), httpHeaders, HttpStatus.CREATED);
    try {
        outputStream.close();
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        outputStream.close();
    }
    return filebyte;
}