利用springboot 重定向到静态资源功能，下载一些文件文件

spring:
  web:
    resources:
      static-locations:  file:uploads/,classpath:static/　　　　#手动设置项目外路径uploads

@Controller
public class DownClass {

    /**
     * 下载app
     * @param response
     * 解释一下，我们在yml里面配置了地址uploads，并且也在项目的根路径（直接在文件夹中，而不是IDEA工具里面）创建uploads/xxx.apk文件。
     */
    @RequestMapping("downApp")
    @ResponseBody
    public void Download(HttpServletResponse response,String version) {
        File directory = new File("");// 参数为空
        String courseFile = "";
        String fileName = "test-"+version+".apk";
        try {
            courseFile = directory.getCanonicalPath();
            System.out.println("path2: "+courseFile);
        } catch (IOException e) {
            e.printStackTrace();
        }
        String filepath = courseFile+"\\uploads\\" + fileName;
        File path = new File(filepath);
        if (!path.exists()) {
            System.out.println("找不到该文件：" + fileName);
            return;
        }else{
            try {
                response.sendRedirect("/" + fileName);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}