SpringMVC拦截器入门案例

1、项目结构

 2、pom.xml

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.itheima</groupId>
    <artifactId>springmvc_test_interceptor</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>war</packaging>


    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
    </properties>

    <dependencies>
        <!-- servlet3.0规范的坐标 -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.1.0</version>
            <scope>provided</scope>
        </dependency>
        <!--jsp坐标-->
        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>jsp-api</artifactId>
            <version>2.1</version>
            <scope>provided</scope>
        </dependency>
        <!--spring的坐标-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.1.9.RELEASE</version>
        </dependency>
        <!--springmvc的坐标-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.1.9.RELEASE</version>
        </dependency>
    </dependencies>

    <!--构建-->
    <build>
        <!--设置插件-->
        <plugins>
            <!--具体的插件配置-->
            <plugin>
                <groupId>org.apache.tomcat.maven</groupId>
                <artifactId>tomcat7-maven-plugin</artifactId>
                <version>2.1</version>
                <configuration>
                    <port>80</port>
                    <path>/</path>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

3、InterceptorController代码

package com.itheima.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;

@Controller
public class InterceptorController {
    @RequestMapping("/handleRun")
    public String handleRun() {
        System.out.println("业务处理器运行------------main");
        return "page.jsp";
    }
}

4、MyInterceptor代码

package com.itheima.interceptor;

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

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
//自定义拦截器需要实现HandleInterceptor接口
public class MyInterceptor implements HandlerInterceptor {
    //处理器运行之前执行
    @Override
    public boolean preHandle(HttpServletRequest request,
                             HttpServletResponse response,
                             Object handler) throws Exception {
        System.out.println("前置运行----a1");
        //返回值为false将拦截原始处理器的运行
        //如果配置多拦截器，返回值为false将终止当前拦截器后面配置的拦截器的运行
        return true;
    }

    //处理器运行之后执行
    @Override
    public void postHandle(HttpServletRequest request,
                           HttpServletResponse response,
                           Object handler,
                           ModelAndView modelAndView) throws Exception {
        System.out.println("后置运行----b1");
    }

    //所有拦截器的后置执行全部结束后，执行该操作
    @Override
    public void afterCompletion(HttpServletRequest request,
                                HttpServletResponse response,
                                Object handler,
                                Exception ex) throws Exception {
        System.out.println("完成运行----c1");
    }

    //三个方法的运行顺序为    preHandle -> postHandle -> afterCompletion
    //如果preHandle返回值为false，三个方法仅运行preHandle
}

5、MyInterceptor2代码

package com.itheima.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 MyInterceptor2 implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request,
                             HttpServletResponse response,
                             Object handler) throws Exception {
        System.out.println("前置运行------a2");
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request,
                           HttpServletResponse response,
                           Object handler,
                           ModelAndView modelAndView) throws Exception {
        System.out.println("后置运行------b2");
    }

    @Override
    public void afterCompletion(HttpServletRequest request,
                                HttpServletResponse response,
                                Object handler,
                                Exception ex) throws Exception {
        System.out.println("完成运行------c2");
    }
}

6、MyInterceptor3代码

package com.itheima.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 MyInterceptor3 implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request,
                             HttpServletResponse response,
                             Object handler) throws Exception {
        System.out.println("前置运行--------a3");
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request,
                           HttpServletResponse response,
                           Object handler,
                           ModelAndView modelAndView) throws Exception {
        System.out.println("后置运行--------b3");
    }

    @Override
    public void afterCompletion(HttpServletRequest request,
                                HttpServletResponse response,
                                Object handler,
                                Exception ex) throws Exception {
        System.out.println("完成运行--------c3");
    }
}

7、spring-mvc.xml

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

    <mvc:annotation-driven/>

    <context:component-scan base-package="com.itheima"/>

    <!--开启拦截器使用-->
    <mvc:interceptors>
        <!--开启具体的拦截器的使用，可以配置多个-->
        <mvc:interceptor>
            <!--设置拦截器的拦截路径，支持*通配-->
            <!--/**         表示拦截所有映射-->
            <!--/*          表示拦截所有/开头的映射-->
            <!--/user/*     表示拦截所有/user/开头的映射-->
            <!--/user/add*  表示拦截所有/user/开头，且具体映射名称以add开头的映射-->
            <!--/user/*All  表示拦截所有/user/开头，且具体映射名称以All结尾的映射-->
            <mvc:mapping path="/*"/>
            <mvc:mapping path="/**"/>
            <mvc:mapping path="/handleRun*"/>
            <!--设置拦截排除的路径，配置/**或/*，达到快速配置的目的-->
            <mvc:exclude-mapping path="/b*"/>
            <!--指定具体的拦截器类-->
            <bean class="MyInterceptor"/>
        </mvc:interceptor>
        <!--配置多个拦截器，配置顺序即为最终运行顺序-->
        <mvc:interceptor>
            <mvc:mapping path="/*"/>
            <bean class="MyInterceptor2"/>
        </mvc:interceptor>
        <mvc:interceptor>
            <mvc:mapping path="/*"/>
            <bean class="MyInterceptor3"/>
        </mvc:interceptor>
    </mvc:interceptors>


</beans>

8、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">

    <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*:spring-mvc.xml</param-value>
        </init-param>
    </servlet>
    <servlet-mapping>
        <servlet-name>DispatcherServlet</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

    <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>

9、page.jsp

<%@page pageEncoding="UTF-8" language="java" contentType="text/html;UTF-8" %>
<html>
<body>
<h1>拦截器测试中...</h1>
</body>
</html>