SpringMVC拦截器

拦截器知识

拦截器(Interceptor)用于对URL请求进行前置/后置过滤
Interceptor与Filter用途相似但实现方式不同
Interceptor底层就是基于Spring AOP面向切面编程实现

拦截器开发流程

Maven添加依赖包servlet-api

 <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.1.0</version>
            <scope>provided</scope>
        </dependency>

实现HandlerInterceptor接口
接口会实现三个方法，拦截的时间分别为：
preHandle-前置执行处理，请求产生之后，Controller处理之前。
postHandle - 目标资源已被Spring MVC框架处理，Controller处理之后，方法的return执行完立马执行这个拦截器。
afterCompletion - 响应文本已经产生，产生响应文本之后。

public class MyInterceptor implements HandlerInterceptor {
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println(request.getRequestURL() + "-准备执行");
        return true;
    }

    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println(request.getRequestURL() + "-目标处理成功");
    }

    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println(request.getRequestURL() + "-响应内容已产生");
    }
}

applicationContext配置过滤地址。
mapping path=“/**”: 拦截所有地址
<bean class=“com.imooc.restful.interceptor.AccessHistoryInterceptor”/>: 拦截之后负责处理的方法类。

    <mvc:interceptors>
        <mvc:interceptor>
            <mvc:mapping path="/**"/>
            <mvc:exclude-mapping path="/resources/**"/>
            <bean class="com.imooc.restful.interceptor.AccessHistoryInterceptor"/>
        </mvc:interceptor>
    </mvc:interceptors>

/<mvc:exclude-mapping path=“/resources/**”/>：哪个路径下的文件不启用拦截器。

多个拦截器的执行顺序

Spring MVC处理流程