SpringBoot下载resources目录下的文件

1.引入SpringBoot和hutool依赖

        <dependency><groupId>cn.hutool</groupId><artifactId>hutool-all</artifactId><version>5.8.22</version></dependency>

2.在项目resources目录下放入模版文件，结构如下：
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3.定义文件下载接口

    @SneakyThrows(IOException.class)@ApiOperation(value = "下载模版文件", notes = "下载模版文件")@RequestMapping(value = "/down_template", method = RequestMethod.GET)public Response<Void> downTemplate(@RequestParam(required = false)String templateName, HttpServletResponse response) {if(StringUtils.isBlank(templateName)){return null;}response.setCharacterEncoding("utf-8");try (InputStream templateInputStream = this.getClass().getResourceAsStream("/template/" + templateName);OutputStream outputStream = response.getOutputStream()) {Asserts.notNull(templateInputStream, "templateInputStream is null");//获取文件字节数组byte[] bytes = IoUtil.readBytes(templateInputStream);//获取文件mimetype,也就是contenttypeFileMagicNumber magicNumber = FileMagicNumber.getMagicNumber(bytes);if(magicNumber != FileMagicNumber.UNKNOWN){response.setContentType(magicNumber.getMimeType());String fileName = URLEncoder.encode("模版文件" + DateUtil.format(new Date(), "yyyyMMdd"), "UTF-8").replaceAll("\\+", "%20");response.setHeader("Content-disposition", "attachment; filename=" + fileName + "." + magicNumber.getExtension());}outputStream.write(bytes, 0, bytes.length);}return null;}