Spring MVC-拦截器

概括
环境
配置拦截器
- 单个拦截器
- 多个拦截器
源码

概括

pringMVC中的拦截器用于拦截控制器方法的执行

环境

 <dependencies>
        <!-- SpringMVC -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.3.1</version>
        </dependency>
        <!-- 日志 -->
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
            <version>1.2.3</version>
        </dependency>
        <!-- ServletAPI -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.1.0</version>
            <scope>provided</scope>
        </dependency>
        <!-- Spring5和Thymeleaf整合包 -->
        <dependency>
            <groupId>org.thymeleaf</groupId>
            <artifactId>thymeleaf-spring5</artifactId>
            <version>3.0.12.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.12.1</version>
        </dependency>

    </dependencies>

<?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">

    <!--自动扫描包-->
    <context:component-scan base-package="com.fly.controller"/>

    <!-- 配置Thymeleaf视图解析器 -->
    <bean id="viewResolver" class="org.thymeleaf.spring5.view.ThymeleafViewResolver">
        <property name="order" value="1"/>
        <property name="characterEncoding" value="UTF-8"/>
        <property name="templateEngine">
            <bean class="org.thymeleaf.spring5.SpringTemplateEngine">
                <property name="templateResolver">
                    <bean class="org.thymeleaf.spring5.templateresolver.SpringResourceTemplateResolver">
                        <!-- 视图前缀 -->
                        <property name="prefix" value="/WEB-INF/templates/"/>
                        <!-- 视图后缀 -->
                        <property name="suffix" value=".html"/>
                        <property name="templateMode" value="HTML5"/>
                        <property name="characterEncoding" value="UTF-8" />
                    </bean>
                </property>
            </bean>
        </property>
    </bean>

    <!--  springMVC.xml  -->
    <mvc:view-controller path="/" view-name="index"/>

    <mvc:annotation-driven>
        <mvc:message-converters>
            <!-- 处理响应中文内容乱码 -->
            <bean class="org.springframework.http.converter.StringHttpMessageConverter">
                <property name="defaultCharset" value="UTF-8" />
                <property name="supportedMediaTypes">
                    <list>
                        <value>text/html</value>
                        <value>application/json</value>
                    </list>
                </property>
            </bean>
        </mvc:message-converters>
    </mvc:annotation-driven>
</beans>

<?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">

    <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>
        <init-param>
            <param-name>forceResponseEncoding</param-name>
            <param-value>true</param-value>
        </init-param>
    </filter>

    <filter-mapping>
        <filter-name>CharacterEncodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

    <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>

</web-app>

配置拦截器

单个拦截器

package com.fly.Interceptors;

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

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * @author 26414
 */
@Component
public class FirstInterceptor implements HandlerInterceptor {


  @Override
  public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
    System.out.println("FirstInterceptor==============preHandle");
    return true;
  }

  @Override
  public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
    System.out.println("FirstInterceptor==============postHandle");
  }

  @Override
  public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
    System.out.println("FirstInterceptor==============afterCompletion");
  }
}

在配置文件中进行配置

<!--  springMVC.xml  -->
    <mvc:interceptors>
        <!--
            第一种方式：
            <bean class="com.fly.Interceptors.FirstInterceptor"/>
            第二种方式：在拦截器上面添加@Component注解，前提是要在自动扫描的范围内
            <ref bean="firstInterceptor"/>
            以上两种方式都是对DispatcherServlet所处理的所有的请求进行拦截
            /*：对所以单层请求映射进行拦截，例如：/test、/info
            /**：对所有请求映射进行拦截
        -->
        <mvc:interceptor>
            <mvc:mapping path="/**"/>
            <mvc:exclude-mapping path="/"/>
            <ref bean="firstInterceptor"/>
        </mvc:interceptor>
    </mvc:interceptors>

package com.fly.controller;

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

/**
 * @author 26414
 */
@Controller
public class InterceptorController {
  
  @RequestMapping("/testInterceptor")
  public String testInterceptor() {
    return "success";
  }
  
}

<!--index.html-->
<a th:href="@{/testInterceptor}">testInterceptor</a>

<!--success.html-->
<h2>success</h2>
</body>

多个拦截器

package com.fly.Interceptors;

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

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * @author 26414
 */
@Component
public class SecondInterceptor implements HandlerInterceptor{
  @Override
  public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
    System.out.println("SecondInterceptor==============preHandle");
    return true;
  }

  @Override
  public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
    System.out.println("SecondInterceptor==============postHandle");
  }

  @Override
  public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
    System.out.println("SecondInterceptor==============afterCompletion");
  }
}

源码

在testInterceptor方法上打断点，以debug模式启动服务器

如果有一个拦截器返回false，interceptorIndex的最大值为返回false的前一个i

1：若每个拦截器的preHandle()都返回true此时多个拦截器的执行顺序和拦截器在SpringMVC的配置文件的配置顺序有关，preHandle()会按照配置的顺序执行，而postHandle()和afterComplation()会按照配置的反序执行。
2：若某个拦截器的preHandle()返回了falsepreHandle()返回false和它之前的拦截器的preHandle()都会执行，postHandle()都不执行，返回false的拦截器之前的拦截器的afterComplation()会执行

posted @ 2021-11-26 20:29 翻蹄亮掌一皮鞋阅读(71) 评论(0) 收藏举报

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Spring MVC-拦截器

概括

环境

配置拦截器

单个拦截器

多个拦截器

源码

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