Java 导出Excel表格

ResponseEntity<byte[]> download() throws IOException {
        String head[] = {"用户编号", "用户名", "姓名", "密码", "身份证", "联系电话", "状态"};

        HttpHeaders headers = new HttpHeaders();
        headers.setCacheControl("no-cache, no-store, must-revalidate");
        headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
        headers.setContentLength(test(head).length);
        headers.setContentDispositionFormData("attachment", URLEncoder.encode("用户信息表.xls", "utf-8"));
        System.out.println(test(head).toString());
        return ResponseEntity.ok()
                .headers(headers)
                .body(test(head));
    }

    public byte[] test(String arr[]){

        List<Customer> petList = customerMapper.selectAll();

        HSSFWorkbook workbook = new HSSFWorkbook();
        HSSFSheet sheet = workbook.createSheet("用户信息表");
        HSSFRow row = sheet.createRow(0);
        for (int i = 0; i < arr.length; i++) {
            row.createCell(i).setCellValue(arr[i]);
        }

        int i = 1;
        for (Customer customer : petList) {
            row = sheet.createRow(i);
            row.createCell(0).setCellValue(customer.getCustomerId());
            row.createCell(1).setCellValue(customer.getCustomerName());
            row.createCell(2).setCellValue(customer.getCustomerUser());
            row.createCell(3).setCellValue(customer.getCustomerPwd());
            row.createCell(4).setCellValue(customer.getCustomerIdcard());
            row.createCell(5).setCellValue(customer.getCustomerPhone());
            row.createCell(6).setCellValue(customer.getCustomerStatus());
            i++;
        }

        ByteArrayOutputStream stream = new ByteArrayOutputStream();
        try {
            workbook.write(stream);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return stream.toByteArray();
    }