Jsp 获取当前访问url

<%
    String realPath = "http://" +
                      request.getServerName() +
                      ":" +
                      request.getServerPort() +
                      request.getContextPath() +
                      request.getServletPath().substring(0, request.getServletPath().lastIndexOf("/") + 1);
                       
    System.out.println(realPath);
%>