从Request对象中可以获取各种路径信息，以下例子：
假设请求的页面是index.jsp,项目是WebDemo，则在index.jsp中获取有关request对象的各种路径信息如下
String path = request.getContextPath();
String basePath = request.getScheme()+://+request.getServerName()+:+request.getServerPort()+path+/;
String remoteAddress=request.getRemoteAddr();
String serv
