SpringMVC应用拦截器判断用户是否登录

约定不等于承诺〃 2023-10-18 09:18 130阅读 0赞

### 拦截器定义 ###

实现HandlerInterceptor接口，实现接口方法。

import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    import org.springframework.web.servlet.HandlerInterceptor;
    import org.springframework.web.servlet.ModelAndView;
    
    public class Interceptor1 implements HandlerInterceptor{
    
     public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object arg2) throws Exception {
      // TODO Auto-generated method stub
      System.out.println("方法前 1");
      //判断用户是否登陆  如果没有登陆  重定向到登陆页面   不放行   如果登陆了  就放行了
      // URL  http://localhost:8080/springmvc-mybatis/login.action
      //URI /login.action
      String requestURI = request.getRequestURI();
      if(!requestURI.contains("/login")){
       String username = (String) request.getSession().getAttribute("USER_SESSION");
       if(null == username){
        response.sendRedirect(request.getContextPath() + "/login.action");
        return false;
       }
      }
      return true;
     }
     public void postHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, ModelAndView arg3)
       throws Exception {
      // TODO Auto-generated method stub
      System.out.println("方法后 1");
      
     }
     public void afterCompletion(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, Exception arg3)
       throws Exception {
      // TODO Auto-generated method stub
      System.out.println("页面渲染后 1");
      
     }
    
    }

### 拦截器配置 ###

在springmvc.xml中配置拦截器

<mvc:interceptors>
       
       <mvc:interceptor>
        <mvc:mapping path="/**"/>
        
        <bean class="com.itheima.springmvc.interceptor.Interceptor1"/>
       </mvc:interceptor>
      </mvc:interceptors>

### 编写登录jsp ###

### 编写用户登录Controller ###

//去登陆的页面
     @RequestMapping(value = "/login.action",method = RequestMethod.GET)
     public String login(){
      return "login";
     }
     @RequestMapping(value = "/login.action",method = RequestMethod.POST)
     public String login(String username
       ,HttpSession httpSession){
      httpSession.setAttribute("USER_SESSION", username);
      return "redirect:/item/itemlist.action";
     }