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。

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