JSP 页面访问用户验证

package com.homer; import java.io.IOException; import java.io.PrintWriter; import javax.servlet.Filter; import javax.servlet.FilterChain; import javax.servlet.FilterConfig; import javax.servlet.ServletException; import javax.servlet.ServletRequest; import javax.servlet.ServletResponse; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; /** * LoginFilter 在web.xml中配置说明 <br> * <filter> * <filter-name>LoginFilter</filter-name> * <filter-class>com.homer.LoginFilter</filter-class> * </filter> * * 配置需要经过userlogin.html登陆过才能访问的区域 <br> * 目前配置方式仅仅是在用户访问page222.jsp的时候才走过滤器，可以配置/*, /user/*等目录进行批量网页过滤<br> * <filter-mapping> * <filter-name>LoginFilter</filter-name> * <url-pattern>/page222.jsp</url-pattern> * </filter-mapping> * */ public class LoginFilter implements Filter { @Override public void init(FilterConfig arg0) throws ServletException { } @Override public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2) throws IOException, ServletException { HttpServletRequest request = (HttpServletRequest)arg0; HttpServletResponse response = (HttpServletResponse)arg1; HttpSession session = request.getSession(); if(session.getAttribute("userinfo") == null) { response.setCharacterEncoding("utf-8"); PrintWriter out = response.getWriter(); out.print("<script>alert('您还没有登录，请登录...'); window.location='userlogin.html' </script>"); out.flush(); out.close(); // request.setAttribute("loginError", "您还没有登录，请登录..."); // request.getRequestDispatcher("userlogin.html").forward(request, response); } else { arg2.doFilter(request, response); } } @Override public void destroy() { } }