filter过滤器之自动登录代码

servlet类

package com.csdn.servlet;import java.io.IOException;import javax.servlet.ServletException;import javax.servlet.http.Cookie;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import com.csdn.domain.User;import com.csdn.service.UserService;import com.csdn.service.UserServiceImpl;public class LoginServlet extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {String username = request.getParameter("username");String password = request.getParameter("password");int logintime = Integer.parseInt(request.getParameter("loginTime"));System.out.println(username + "--" + password + "--" + logintime);UserServiceImpl impl = new UserService();User user = impl.find(username, password);if (user != null) {request.getSession().setAttribute("user", user);Cookie cookie1 = new Cookie("username", user.getUsername());Cookie cookie2 = new Cookie("password", user.getPassword());cookie1.setMaxAge(logintime);cookie2.setMaxAge(logintime);cookie1.setPath("/filter_test");cookie2.setPath("/filter_test");response.addCookie(cookie1);response.addCookie(cookie2);response.sendRedirect("/filter_test/success.jsp");} else {request.setAttribute("message", "用户名或密码错误");request.getRequestDispatcher("/message.jsp");}}public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {doGet(request, response);}}

过滤器：

package com.csdn.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.http.Cookie;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import com.csdn.domain.User;import com.csdn.service.UserService;import com.csdn.service.UserServiceImpl;public class FilterTest implements Filter {public void destroy() {// TODO Auto-generated method stub}public void doFilter(ServletRequest request, ServletResponse response,FilterChain chain) throws IOException, ServletException {HttpServletRequest req = (HttpServletRequest) request;HttpServletResponse resp = (HttpServletResponse) response;User user = (User) req.getSession().getAttribute("user");if (user != null) {chain.doFilter(req, resp);return;}String username = null;String password = null;Cookie[] cookie = req.getCookies();for (int i = 0; cookie != null && i < cookie.length; i++) {if (cookie[i].getName().equals("username")) {username = cookie[i].getValue();}if (cookie[i].getName().equals("password")) {password = cookie[i].getValue();}}if (username == null && password == null) {               chain.doFilter(req, resp);               return;}UserServiceImpl impl = new UserService();User user1 = impl.find(username);String save_password = user1.getPassword();if(!password.equals(save_password)){chain.doFilter(req, resp);return;}req.getSession().setAttribute("user", user1);chain.doFilter(req, resp);}public void init(FilterConfig filterConfig) throws ServletException {// TODO Auto-generated method stub}}