SpringMVC拦截器

1 拦截器（interceptor）的作用

SpringMVC的拦截器类似于Servlet开发中的过滤器Filter，用于对处理器进行预处理和后处理

将拦截器按一定的顺序连接成链，这条链称为拦截器链（Interceptor chain）。在访问被拦截的方法或字段时，拦截器链中的拦截器就会按其之前定义的顺序被调用。拦截器也是AOP思想的具体实现

2 拦截器和过滤器的区别

3 自定义拦截器

（1）创建拦截器类实现HandlerInterceptor接口

（2）配置拦截器（spring-mvc.xml中配）

（3）测试拦截器的拦截效果

4 拦截器方法说明

案例：页面初始的情况

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.company</groupId>
    <artifactId>spring_interceptor</artifactId>
    <version>1.0-SNAPSHOT</version>

    <packaging>war</packaging>

    <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>5.2.9.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.0.5.RELEASE</version>
        </dependency>
    </dependencies>

</project>

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_4_0.xsd"
         version="4.0">

    <!--配置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:spring-mvc.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>
</web-app>

spring-mvc.xml

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

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xmlns:context="http://www.springframework.org/schema/context"
       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/context http://www.springframework.org/schema/context/spring-context.xsd
       http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd
">

    <!-- 1、mvc注解驱动-->
    <mvc:annotation-driven/>
    <!-- 2、配置视图解析器-->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/"/>
        <property name="suffix" value=".jsp"/>
    </bean>
    <!-- 3、静态资源权限开放-->
    <mvc:default-servlet-handler/>
    <!-- 4、组件扫描，扫描Controller-->
    <context:component-scan base-package="com.company.controller"/>

</beans>

index.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
    <p>ssssssdss!!!${name}</p>
</body>
</html>

TargetController.java

package com.company.controller;

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

@Controller
public class TargetController {
    @RequestMapping("/target")
    public ModelAndView show() {
        System.out.println("目标资源执行...");
        ModelAndView modelAndView = new ModelAndView();
        modelAndView.addObject("name", "company");
        modelAndView.setViewName("index");
        return modelAndView;
    }
}

浏览器中

下面来看看加入拦截器的案例

MyInterceptor1.java

package com.company.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 MyInterceptor1 implements HandlerInterceptor {
    // 在目标方法执行之前 执行
    public boolean preHandle(javax.servlet.http.HttpServletRequest request,
        javax.servlet.http.HttpServletResponse response, Object handler) throws Exception {
        System.out.println("preHandle....");
        return true;
    }

    // 在目标方法执行之后 视图返回之前执行
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
        ModelAndView modelAndView) throws Exception {
        System.out.println("postHandle....");
    }

    // 在整个流程都执行完毕后 执行
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
        throws Exception {
        System.out.println("afterCompletion....");
    }
}

　　在spring-mvc.xml中配置拦截器

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

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xmlns:context="http://www.springframework.org/schema/context"
       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/context http://www.springframework.org/schema/context/spring-context.xsd
       http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd
">

    <!-- 1、mvc注解驱动-->
    <mvc:annotation-driven/>
    <!-- 2、配置视图解析器-->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/"/>
        <property name="suffix" value=".jsp"/>
    </bean>
    <!-- 3、静态资源权限开放-->
    <mvc:default-servlet-handler/>
    <!-- 4、组件扫描，扫描Controller-->
    <context:component-scan base-package="com.company.controller"/>
    <!-- 配置拦截器-->
    <mvc:interceptors>
        <mvc:interceptor>
        <!--对那些资源执行拦截操作，/** 代表对所有的资源执行拦截-->
            <mvc:mapping path="/**"/>
            <bean class="com.company.interceptor.MyInterceptor1"/>
        </mvc:interceptor>
    </mvc:interceptors>

</beans>

pom.xml添加servlet依赖

<?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.company</groupId>
    <artifactId>spring_interceptor</artifactId>
    <version>1.0-SNAPSHOT</version>

    <packaging>war</packaging>

    <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.2.9.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>5.2.9.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.0.5.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>javax.servlet.jsp-api</artifactId>
            <version>2.2.1</version>
        </dependency>
    </dependencies>

</project>

在浏览器中输入

看控制台上打印

注意：

下面配置拦截后转发到另外一个页面上error.jsp

package com.company.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 MyInterceptor1 implements HandlerInterceptor {
    // 在目标方法执行之前 执行
    public boolean preHandle(HttpServletRequest request,
        HttpServletResponse response, Object handler) throws Exception {
        System.out.println("preHandle....");
        String param = request.getParameter("param");
        if ("yes".equals(param)) {
            return true;
        } else {
            request.getRequestDispatcher("error").forward(request, response);
            return false;
        }

    }

    // 在目标方法执行之后 视图对象返回之前执行
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
        ModelAndView modelAndView) throws Exception {
        modelAndView.addObject("name", "wwhhdhd");
        System.out.println("postHandle....");
    }

    // 在整个流程都执行完毕后 执行
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
        throws Exception {
        System.out.println("afterCompletion....");
    }
}

posted @ 2021-01-07 14:30 GumpYan 阅读(357) 评论(0) 收藏举报

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Gump Yan

SpringMVC拦截器

1 拦截器（interceptor）的作用

2 拦截器和过滤器的区别

3 自定义拦截器

4 拦截器方法说明

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