重新学javaweb---过滤器应用--30天自动登录

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登陆login.jsp

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <head>  </head>  <body>    <h1>用户登录</h1><hr>    <form action="${pageContext.request.contextPath }/servlet/LoginServlet" method="POST">        用户名<input type="text" name="name" />        密码<input type="password" name="password" />        <input type="checkbox" name="autologin" value="true"/>30天内自动登陆        <input type="submit" value="登录"/>     </form>  </body></html>

loginServlet.java

public class LoginServlet extends HttpServlet {    public void doGet(HttpServletRequest request, HttpServletResponse response)            throws ServletException, IOException {        //1.获取用户名密码        String name = request.getParameter("name");        String password  = MD5Utils.md5(request.getParameter("password"));        //2.校验用户名密码        String sql = "select * from user where name = ? and password = ? ";        User user = null;        try {            QueryRunner runner = new QueryRunner(DaoUtils.getSource());            user = runner.query(sql, new BeanHandler<User>(User.class),name,password);        } catch (SQLException e) {            e.printStackTrace();        }        if(user == null){            response.getWriter().write("用户名密码不正确");            return;        }else{            //3.登录用户                request.getSession().setAttribute("user", user);                //如果用户勾选过30天内自动登陆,发送自动登陆cookie                if("true".equals(request.getParameter("autologin"))){                    Cookie autologinC = new Cookie("autologin",user.getName()+":"+user.getPassword());                    autologinC.setPath(request.getContextPath());                    autologinC.setMaxAge(3600*24*30);                    response.addCookie(autologinC);                }            //4.重定向到主页                response.sendRedirect(request.getContextPath()+"/index.jsp");        }    }    public void doPost(HttpServletRequest request, HttpServletResponse response)            throws ServletException, IOException {        doGet(request, response);    }}

logoutServlet.java

public class LogoutServlet extends HttpServlet {    public void doGet(HttpServletRequest request, HttpServletResponse response)            throws ServletException, IOException {        if(request.getSession(false)!=null){            request.getSession().invalidate();            //删除自动登陆cookie            Cookie autologinC = new Cookie("autologin","");            autologinC.setPath(request.getContextPath());            autologinC.setMaxAge(0);            response.addCookie(autologinC);        }        response.sendRedirect(request.getContextPath()+"/index.jsp");    }    public void doPost(HttpServletRequest request, HttpServletResponse response)            throws ServletException, IOException {        doGet(request, response);    }}

自动登陆的过滤器代码：

public class AutologinFilter implements Filter {    public void destroy() {    }    public void doFilter(ServletRequest request, ServletResponse response,            FilterChain chain) throws IOException, ServletException {        HttpServletRequest req = (HttpServletRequest) request;        HttpServletResponse resp = (HttpServletResponse) response;        //1.只有未登录的用户才能自动登陆        if(req.getSession(false)==null || req.getSession().getAttribute("user")==null){            //2.只有带了自动登陆cookie的用户才能自动登陆            Cookie [] cs = req.getCookies();            Cookie findC = null;            if(cs!=null){                for(Cookie c : cs){                    if("autologin".equals(c.getName())){                        findC = c;                        break;                    }                }            }            if(findC!=null){                //3.自动登录Cookie中保存的用户名密码都需要是正确的才能自动登陆                String name = findC.getValue().split(":")[0];                String password= findC.getValue().split(":")[1];                String sql = "select * from user where name = ? and password = ? ";                User user = null;                try {                    QueryRunner runner = new QueryRunner(DaoUtils.getSource());                    user = runner.query(sql, new BeanHandler<User>(User.class),name,password);                } catch (SQLException e) {                    e.printStackTrace();                }                if(user!=null){                    req.getSession().setAttribute("user", user);                }            }        }        //无论是否自动登陆,都放行资源        chain.doFilter(request, response);    }    public void init(FilterConfig filterConfig) throws ServletException {    }}

乱码解决的过滤器见上一篇文章。

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