package com.learning.web.servlet;import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;import com.learning.domain.User;
import com.learning.service.UserService;@WebServlet("/servlet/loginServlet")
public class LoginServlet extends HttpServlet {private static final long serialVersionUID = 1L;protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {String username = request.getParameter("username");String password = request.getParameter("password");String autologin = request.getParameter("autologin");UserService userService=new UserService();User user = userService.findUser(username, password);//user不为null，则登录成功if (user!=null) {//创建cookie来保存用户信息Cookie cookie=new Cookie("user", user.getUsername()+"&"+user.getPassword());cookie.setPath("/");//autologin不为null，则记住了登录状态if (autologin!=null) {cookie.setMaxAge(1*60*60*24);//一天的有效时间
                }else {cookie.setMaxAge(0);}response.addCookie(cookie);request.getSession().setAttribute("user", user);request.getRequestDispatcher("/home.jsp").forward(request, response);}else {response.sendRedirect(request.getContextPath()+"/homeLogin.jsp");}}protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {doGet(request, response);}}

package com.learning.web.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.annotation.WebInitParam;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import javax.servlet.jsp.jstl.core.Config;import com.learning.domain.User;
import com.learning.service.UserService;@WebFilter(urlPatterns="/*",initParams={@WebInitParam(name="autologin",value="login"),@WebInitParam(name="",value="")})
public class AutoFilter implements Filter{private FilterConfig filterConfig;@Overridepublic void destroy() {}@Overridepublic void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)throws IOException, ServletException {// 转换对象HttpServletRequest httpServletRequest = (HttpServletRequest) request;HttpServletResponse httpServletResponse = (HttpServletResponse) response;// 获得访问的路径String uri = httpServletRequest.getRequestURI();String contextPath = httpServletRequest.getContextPath();uri = uri.substring(contextPath.length() + 1);// 获得初始化参数String login = filterConfig.getInitParameter("autologin");System.out.println("直接通行的路径："+login);// 不包含"login"的路径就要进行过滤 （xxxlogin.jsp 不需要自动登录）if (!uri.contains(login)) {HttpSession session = httpServletRequest.getSession();User u = (User) session.getAttribute("user");if (u != null) {System.out.println("session不为null");chain.doFilter(request, response);} else {// 处理业务逻辑// 1.获得cookie 得到User的信息
String username = "";String password = "";UserService userService = new UserService();Cookie[] cookies = httpServletRequest.getCookies();for (int i = 0;cookies!=null&& i < cookies.length; i++) {        if ("user".equals(cookies[i].getName())) {String string = cookies[i].getValue();String[] values = string.split("&");username = values[0];password = values[1];User user = userService.findUser(username, password);// 不为空则放入sessionif (user != null) {System.out.println("自动登录了");httpServletRequest.getSession().setAttribute("user", user);}}}}}// 2.放行
        chain.doFilter(request, response);}@Overridepublic void init(FilterConfig filterConfig) throws ServletException {this.filterConfig=filterConfig;}}