StringMVC（拦截器）

单个拦截器

使用jar包

创建FirstController.java

@Controller
public class FirstController {
    @RequestMapping("/first.do")
     public String doFirst(){
         return "/index.jsp";
     }
}

创建连接器类FirstInterceptor.java

/**
 * Created by Happy on 2017-01-12.  alt+Enter 自动导入包
 */
public class FirstInterceptor implements HandlerInterceptor {

    @Override
    public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o) throws Exception {
        System.out.println("==================preHandle===============");
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {
        System.out.println("==================postHandle===============");
    }

    @Override
    public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {
        System.out.println("==================afterCompletion===============");
    }
}

编写applicationContext.xml 配置（包扫描器/拦截器）

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:aop="http://www.springframework.org/schema/aop"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
     xsi:schemaLocation="
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd
        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd
        ">

   <!-- 配置包扫描器-->
       <context:component-scan base-package="cn.happy.interceptor"></context:component-scan>

    <!--配置拦截器-->
     <mvc:interceptors>
         <mvc:interceptor>
             <mvc:mapping path="/**" />
             <bean class="cn.happy.interceptor.FirstInterceptor"></bean>
         </mvc:interceptor>
     </mvc:interceptors>
</beans>

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
         version="3.1">
    <!--核心控制器-->
    <servlet>
        <servlet-name>sprigmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:applicationContext.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>sprigmvc</servlet-name>
        <url-pattern>*.do</url-pattern>
    </servlet-mapping>
</web-app>

单个拦截器请求过程图

多个拦截器

在单个拦截器的基础上多添加一个连接器类SFirstInterceptor.java

/**
 * Created by Happy on 2017-01-12.  alt+Enter 自动导入包
 */
public class FirstInterceptor implements HandlerInterceptor {

    @Override
    public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o) throws Exception {
        System.out.println("=========S=========preHandle===============");
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {
        System.out.println("=========S=========postHandle===============");
    }

    @Override
    public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {
        System.out.println("==========S========afterCompletion===============");
    }
}

更改applicationContext.xml陪置（下列代码中带下划线的是增加内容）

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:aop="http://www.springframework.org/schema/aop"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
     xsi:schemaLocation="
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd
        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd
        ">

   <!-- 配置包扫描器-->
       <context:component-scan base-package="cn.happy.interceptor"></context:component-scan>

    <!--配置攔截器-->
     <mvc:interceptors>
         <mvc:interceptor>
             <mvc:mapping path="/**" />
             <bean class="cn.happy.interceptor.FirstInterceptor"></bean>
         </mvc:interceptor>
<mvc:interceptor>
             <mvc:mapping path="/**" />
             <bean class="cn.happy.interceptor.SFirstInterceptor"></bean>
         </mvc:interceptor>
     </mvc:interceptors>
</beans>

多拦截器请求过程图