下载excel模板

controller层：

@RequestMapping(value = "/template-download", method = RequestMethod.GET)
public ResponseEntity<byte[]> templateDownload() {
    return xxService.templateDownload();
}

service层：

private static final String[] EXCEL_HEADER_NAMES = {"姓名", "年龄"};

public ResponseEntity<byte[]> templateDownload() throws RuntimeException {
    logger.debug("进入了templateDownload方法");
    try {
        XSSFWorkbook wb = createExcelTemplate();

        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
        headers.setContentDispositionFormData("attachment", "download_template.xlsx");

        //创建一个字节数组输出流对象
        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
        wb.write(outputStream);

        ResponseEntity<byte[]> returnFile = new ResponseEntity<byte[]>(outputStream.toByteArray(), headers, HttpStatus.OK);

        outputStream.close();
        return returnFile;
    } catch (Exception ex) {

　　　　　　logger.error(ex.getMessage());

　　　　　　throw new RuntimeException(ex);

    }
}

/**
 * 创建excel模版
 */
private XSSFWorkbook createExcelTemplate() {
    List<String> headers = createHeaders();
    if (CollectionUtils.isEmpty(headers)) {
        throw new RuntimeException("下载模版失败");
    }
    XSSFWorkbook wb = new XSSFWorkbook();
    ExcelUtils.createExcel(wb, headers);
    return wb;
}

/**
 * 创建header list
 *
 * @return
 */
private List<String> createHeaders() {
    List<String> headers = new ArrayList<>();
    for (String excelHeaderName : EXCEL_HEADER_NAMES) {
        headers.add(excelHeaderName);
    }
    return headers;
}

ExcelUtils:

/**
 * 创建excel
 */
public static void createExcel(XSSFWorkbook wb, List<String> headers) throws RuntimeException{
    try {
        XSSFSheet sheet = wb.createSheet();
        //在sheet里创建第一行，这里即是表头
        XSSFRow rowTitle = sheet.createRow(0);

        //写入表头的每一个列
        for (int i = 0; i < headers.size(); i++) {
            //创建单元格
            rowTitle.createCell(i).setCellValue(headers.get(i));
        }
    }catch (Exception e) {
        logger.error(e.getMessage());

        throw new RuntimeException(e);
    }
}