Request 获取请求的 URL

端口：8080

request.getServerPort();

服务器：localhost

request.getServerName();

项目名：wechat-ssm

request.getContextPath();

ServletPath: servlet/demoServlet

request.getServletPath()；

RequestURI: wechat-ssm/servlet/demoServlet

request.getRequestURI()；

整个请求路径：http://localhost:8080/wechat-ssm/servlet/demoServlet

request.getRequestURI()；

项目的路径：D:\Tomcat7.0\webapps\wechat-ssm

request.getSession().getServletContext().getRealPath("");