拦截器的实现

拦截器的实现

创建拦截器必须实现HandlerInterceptor以及重写三个方法
preHandle
postHandle
afterCompletion

public class LoginHandlerIntercepor implements HandlerInterceptor {    
    @Override    
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, 
        Object handler) throws Exception {        
        Object obj = request.getSession().getAttribute("loginUser");        
        if(obj == null){            
            request.getRequestDispatcher("/main.html").forward(request,response);            
            return false;        
        }else{            
             return true;        
        }   
    }    
    @Override    
    public void postHandle(HttpServletRequest request, HttpServletResponse response, 
        Object handler, ModelAndView modelAndView) throws Exception {  
        
        }    
    @Override    
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, 
        Object handler, Exception ex) throws Exception {    
        
        }
   }