spring：十、springMVC拦截器

目录

包结构

坐标引入

mvc配置文件springmvc.xml

web.xml配置

控制器

拦截器

多拦截器执行顺序：

包结构

坐标引入

 <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>3.8.1</version>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.3.7</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.3.7</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>4.0.1</version>
            <scope>compile</scope>
        </dependency>
    </dependencies>

mvc配置文件springmvc.xml

<?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: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
         https://www.springframework.org/schema/context/spring-context.xsd
         http://www.springframework.org/schema/mvc
         https://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <!--组件扫描  主要扫描controller-->
    <context:component-scan base-package="demo.controller" />
    <!--启用spring的一些annotation -->
    <context:annotation-config/>
    <!--配置mvc注解驱动-->
    <mvc:annotation-driven/>
    <!--SpringMVC提供的通用资源放行方式-->
    <mvc:default-servlet-handler/>


    <!--    视图解析器-->
        <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
            <property name="prefix" value="/WEB-INF/page/" />
            <property name="suffix" value=".jsp" />
        </bean>


    <!-- 声明拦截器 -->
        <mvc:interceptors>
            <!-- 声明第一个拦截器 -->
            <mvc:interceptor>
                <!--
                    指定拦截器的拦截地址
                    path: 拦截器的uri地址，使用 ** 通配符
                -->
                <mvc:mapping path="/**"/>
                <!-- 指定使用的拦截器 -->
                <bean class="demo.interceptor.MyInterceptor" />
            </mvc:interceptor>

            <!-- 声明第二个拦截器 -->
            <mvc:interceptor>
                <!--
                    指定拦截器的拦截地址
                    path: 拦截器的uri地址，使用 ** 通配符
                -->
                <mvc:mapping path="/**"/>
                <!-- 指定使用的拦截器 -->
                <bean class="demo.interceptor.MyInterceptor2" />
            </mvc:interceptor>

            <!-- 声明第二个拦截器 -->
            <mvc:interceptor>
                <!--
                    指定拦截器的拦截地址
                    path: 拦截器的uri地址，使用 ** 通配符
                -->
                <mvc:mapping path="/**"/>
                <!-- 指定使用的拦截器 -->
                <bean class="demo.interceptor.MyInterceptor3" />
            </mvc:interceptor>

        </mvc:interceptors>
</beans>

web.xml配置

<?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_4_0.xsd"
         version="4.0">
  <!--    springmvc的前端控制器-->
  <servlet>
    <servlet-name>DispatcherServlet</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>classpath:springmvc.xml</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
  </servlet>

  <servlet-mapping>
    <servlet-name>DispatcherServlet</servlet-name>
    <url-pattern>/</url-pattern>
  </servlet-mapping>


  <!--乱码过滤器-->
  <filter>
    <filter-name>CharacterEncodingFilter</filter-name>
    <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
    <init-param>
      <param-name>encoding</param-name>
      <param-value>UTF-8</param-value>
    </init-param>
  </filter>
  <filter-mapping>
    <filter-name>CharacterEncodingFilter</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>

</web-app>

控制器

package demo.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class MyController {

    @RequestMapping("/index")
    public String getIndex(){
        System.out.println("index....");
        return "index";
    }


}

拦截器

package demo.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 {
    //preHandle在控制前执行
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("preHandle 前置拦截111");

        //返回true后才可以执行控制器方法
        return true;
    }

    //postHandle在控制后执行
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("postHandle 后置拦截111");
    }

    //afterCompletion最终执行
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("afterCompletion 最终拦截111");
    }
}

多拦截器执行顺序：

正常执行顺序：

当拦截器2前置拦截返回false：

当拦截器3前置拦截返回false：