SpringMVC中的拦截器

1、编写拦截类实现HandlerInterceptor接口

package net.togogo.interceptor;

import org.springframework.web.servlet.HandlerInterceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class MyInterceptor implements HandlerInterceptor {
    /**
     * 预处理，controller方法执行前
     * return true 放行，执行下一个拦截器，如果没有，执行controller中的方法
     * return false 不放行。
     * @param request
     * @param response
     * @param handler
     * @return
     * @throws Exception
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("MyInterceptor执行。。。。");
        return true;
    }
}

2、配置拦截器

 <!--配置多个拦截器-->
    <mvc:interceptors>
        <!--配置单个拦截器-->
        <mvc:interceptor>
            <!--要拦截的具体方法-->
            <mvc:mapping path="/user/*"/>
            <!--不要拦截的具体方法-->
<!--            <mvc:exclude-mapping path=""/>-->
            <!--配置拦截器对象-->
            <bean id="myInterceptor" class="net.togogo.interceptor.MyInterceptor"/>
        </mvc:interceptor>
    </mvc:interceptors>

3、拦截器接口方法

package net.togogo.interceptor;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class MyInterceptor implements HandlerInterceptor {
    /**
     * 预处理，controller方法执行前
     * return true 放行，执行下一个拦截器，如果没有，执行controller中的方法
     * return false 不放行。
     * @param request
     * @param response
     * @param handler
     * @return
     * @throws Exception
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("MyInterceptor执行。。。。前");
//        request.getRequestDispatcher("/WEB-INF/pages/error.jsp").forward(request,response);
        return true;
    }

    /**
     * 后处理方法 controller方法执行后，sucess.jsp执行之前
     * @param request
     * @param response
     * @param handler
     * @param modelAndView
     * @throws Exception
     */
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("MyInterceptor执行。。。。后");
//        request.getRequestDispatcher("/WEB-INF/pages/error.jsp").forward(request,response);
    }

    /**
     * sucess.jsp页面执行后，该方法会执行
     * @param request
     * @param response
     * @param handler
     * @param ex
     * @throws Exception
     */
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("MyInterceptor执行。。。。最后");
    }
}

4、多个拦截器时