SpringBoot实现接口提供下载文件

	public ResponseEntity<FileSystemResource> 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;
    }