如何获取客户端IP、操作系统、浏览器

request.getRemoteAddr();//获取IP

request.getHeader("User-Agent");//获取操作系统信息、浏览器信息。

 1     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 2 //        response.sendError(404, "不给看");//设置状态码
 3 //        response.setHeader("Location", "/Servlet/BServlet");//重定向
 4 //        response.sendError(302);
 5         request.setCharacterEncoding("utf-8");
 6         response.setContentType("text/html;charset=utf-8");
 7         
 8 //        PrintWriter p = response.getWriter();
 9 //        p.write("5秒钟后自动跳转！");
10 //        response.setHeader("refresh", "5;url=/Servlet/BServlet");//定时器
11         System.out.println(request.getRemoteAddr());
12         String userAgent =request.getHeader("User-Agent");
13         if(userAgent.toLowerCase().contains("firefox")){
14             System.out.println("火狐");
15         }else if(userAgent.toLowerCase().contains("chrome")){
16             System.out.println("谷歌");
17         }else if(userAgent.toLowerCase().contains("msie")){
18             System.out.println("ie");
19         }
20         
21     }