在网上找了半天，获取springboot resource下面的文件，各种实验，最终解决了，废话不说直接上代码
/**
* 描述：下载外部案件导入模板
* @throws Exception
*/
@RequestMapping(value = "/downloadExcel")
@ResponseBody
public void downloadExcel(HttpServletResponse res, HttpServletRequest req,String name) throws Exception {
String fileName = name+".xlsx";
ServletOutputStream out;
res.setContentType("multipart/form-data");
res.setCharacterEncoding("UTF-8");
res.setContentType("text/html");
String filePath = getClass().getResource("/template/" + fileName).getPath();
String userAgent = req.getHeader("User-Agent");
if (userAgent.contains("MSIE") || userAgent.contains("Trident")) {
fileName = java.net.URLEncoder.encode(fileName, "UTF-8");
} else {
// 非IE浏览器的处理：
fileName = new String((fileName).getBytes("UTF-8"), "ISO-8859-1");
}
filePath = URLDecoder.decode(filePath, "UTF-8");
res.setHeader("Content-Disposition", "attachment;fileName=" + fileName);
FileInputStream inputStream = new FileInputStream(filePath);
out = res.getOutputStream();
int b = 0;
byte[] buffer = new byte[1024];
while ((b = inputStream.read(buffer)) != -1) {
// 4.写到输出流(out)中
out.write(buffer, 0, b);
}
inputStream.close();
if (out != null) {
out.flush();
out.close();
}
}