过滤器过滤页面，实现自动登录

若系统登录成功一次，则再次启动不需要填写用户名密码，直接跳转首页。

思路

传一个值确定是否满足自动登录条件，若满足加一个过滤器，将登录页面过滤即可。

代码

自动登录传值

//保存当前的用户信息User user = new User(username, password, 1);request.getSession().setAttribute("user", user);

过滤器过滤login.html页面

package filter;import java.io.IOException;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.annotation.WebFilter;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession;import bean.User;/** * Servlet implementation class LoginFilter */@WebFilter("/login.html")public class LoginFilter implements Filter {
              /**     * @see HttpServlet#HttpServlet()     */    public LoginFilter() {
   }	@Override	public void destroy() {
   		System.out.println("已销毁");	}	@Override	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)			throws IOException, ServletException {
   		HttpServletRequest req = (HttpServletRequest) request;		HttpServletResponse res = (HttpServletResponse) response;				HttpSession  session = req.getSession();		//根据User对象去取		User user = (User)session.getAttribute("user");		//判断		if(user!= null){
   		if(user.getIsAutoLogin()!= 0){
     //说明勾选了自动登陆			if("tom".equals(user.getUsername())&&"123".equals(user.getPassword())){
   				//判断帐号密码是否正确				//正确之后内部跳转主页index.html				req.getRequestDispatcher("index.html").forward(request, response);;  //用来过滤单个页面			}else {
   				//帐号密码不正确				//跳转到密码错误的一个界面				//res.sendRedirect("/Day03Html/passwderror.html");				chain.doFilter(request, response);							}		}else {
     //说明不需要自动登陆，也不需要过滤器			chain.doFilter(request, response);			//chain.doFilter(req, res);		}		}else {
   			chain.doFilter(request, response);		}	}	@Override	public void init(FilterConfig fConfig) throws ServletException {
   		System.out.println("初始化");			}}

转载地址：http://itpen.baihongyu.com/

你可能感兴趣的文章