package cn.woniubushiniu.controller;import cn.woniubushiniu.po.User;import org.springframework.stereotype.Controller;import org.springframework.ui.Model;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestMethod;import javax.servlet.http.HttpSession;@Controllerpublic class UserController {  /**   * 向用戶登錄頁面跳轉   */  @RequestMapping(value = "/login",method = RequestMethod.GET)  public String toLogin(){    return "login";  }  /**   * 用戶登錄   * @param user   * @param model   * @param session   * @return   */  @RequestMapping(value = "/login",method = RequestMethod.POST)  public String login(User user, Model model, HttpSession session){    //獲取用戶名和密碼    String username=user.getUsername();    String password=user.getPassword();    //些處橫板從數據庫中獲取對用戶名和密碼后進行判斷    if(username!=null&&username.equals("admin")&&password!=null&&password.equals("admin")){      //將用戶對象添加到Session中      session.setAttribute("USER_SESSION",user);      //重定向到主頁面的跳轉方法      return "redirect:main";    }    model.addAttribute("msg","用戶名或密碼錯誤，請重新登錄！");    return "login";  }  @RequestMapping(value = "/main")  public String toMain(){    return "main";  }    @RequestMapping(value = "/logout")  public String logout(HttpSession session){    //清除session    session.invalidate();    //重定向到登錄頁面的跳轉方法    return "redirect:login";  }  }

public class LoginInterceptor implements HandlerInterceptor {  @Override  public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object o) throws Exception {    //獲取請求的RUi:去除http:localhost:8080這部分剩下的    String uri = request.getRequestURI();    //UTL:除了login.jsp是可以公開訪問的，其他的URL都進行攔截控制    if (uri.indexOf("/login") >= 0) {      return true;    }    //獲取session    HttpSession session = request.getSession();    User user = (User) session.getAttribute("USER_SESSION");    //判斷session中是否有用戶數據，如果有，則返回true，繼續向下執行    if (user != null) {      return true;    }    //不符合條件的給出提示信息，并轉發到登錄頁面    request.setAttribute("msg", "您還沒有登錄，請先登錄！");    request.getRequestDispatcher("/WEB-INF/jsp/login.jsp").forward(request, response);    return false;  }  @Override  public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {  }  @Override  public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {  }}

<!--登錄攔截器-->    <mvc:interceptor>      <mvc:mapping path="/**"/>      <bean class="cn.woniubushiniu.interceptor.LoginInterceptor"/>    </mvc:interceptor>  </mvc:interceptors>

<!--配置前端控制器-->  <servlet>    <servlet-name>springmvc</servlet-name>    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>    <init-param>      <param-name>contextConfigLocation</param-name>      <param-value>classpath:springmvc-config.xml</param-value>    </init-param>    <load-on-startup>1</load-on-startup>  </servlet>  <servlet-mapping>    <servlet-name>springmvc</servlet-name>    <url-pattern>/</url-pattern>  </servlet-mapping>