springmvc(9)拦截器

1.实现拦截器：

a)java类实现HandlerInterceptor接口

public class MyInterceptor implements HandlerInterceptor {
    //在请求处理的方法执行之前执行
    //如果返回true那么执行下一个拦截器，如果返回false那么不执行下一个拦截器
    @Override
    public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o) throws Exception {
        System.out.println("--------------处理前--------------");
        return true;
    }
    //在请求处理的方法执行之后执行
    @Override
    public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {
        System.out.println("--------------处理后-------------");
    }
    //在DispatcherServlet处理后执行----执行清理工作
    @Override
    public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {

    }
}

b)配置拦截器

  <!--拦截器配置-->
    <mvc:interceptors>
        <mvc:interceptor>
            <!--
            /**包括路径及其子路径
            /admin/* - 拦截的是/admin/add,/admin/list 等 /admin/user/add不会被拦截
            /admin/**  上面的这些都会被拦截
            -->
            <mvc:mapping path="/**"/>
            <!--对应的拦截器-->
            <bean class="com.app.interceptor.MyInterceptor"></bean>
        </mvc:interceptor>
    </mvc:interceptors>