springboot文件上传保存到resources里,用System.getProperty("user.dir");参数即可获得项目相对路径。（ps：不知道是不是springboot内嵌tomcat容器的原因，用网上的request.getServletContext().getRealPath("/")方法获得的路径不是项目路径，而是c盘下一个tomcat目录路径）保存成...

Access to XMLHttpRequest at 'localhost:8081/book/getAll' from origin 'http://localhost:8080' has been blocked by CORS policy: Cross origin requests are only supported for protocol schemes: http, data,