SpringMVC拦截器的配置及其细节

谁践踏了优雅 2024-04-03 09:00 64阅读 0赞

###### 1.拦截器的三个方法： ######

> preHandle():在控制器方法执行之前执行，其返回值表示对控制器方法的拦截(false)或放行(true)  
> postHandle():在控制器方法执行之后执行  
> afterCompletion():在控制器方法执行之后，且渲染视图完毕后执行

###### 2.多个拦截器的执行顺序 和在SpringMVC的配置文件中配置的顺序有关 ######

> preHandle()按照配置的顺序执行，而postHandle()和afterCompletion()按照配置的反序执行

###### 3.若拦截器中有某个拦截器的preHandle()返回了false ######

> 拦截器的preHandle()返回false和它之前的拦截器的preHandle()都会执行  
> 所有的拦截器的postHandle()都不执行  
> 拦截器的preHandle()返回false之前的拦截器的afterCompletion()会执行

*以下是具体的配置：*  
**需要注意的是SpringMVC中的拦截器需要实现HandlerInterceptor，SpringMVC的拦截器必须在SpringMVC的配置文件中进行配置**

<?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">
    
        
        <context:component-scan base-package="com.qcw"/>
    
        
        <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">
                            
                            <property name="prefix" value="/WEB-INF/templates/"/>
                            
                            <property name="suffix" value=".html"/>
                            <property name="templateMode" value="HTML5"/>
                            <property name="characterEncoding" value="UTF-8" />
                        </bean>
                    </property>
                </bean>
            </property>
        </bean>
    
        
        <mvc:default-servlet-handler/>
    
        
        <mvc:annotation-driven/>
        
        <mvc:view-controller path="/" view-name="index"></mvc:view-controller>
    
        
        <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver"></bean>
    
    
        <mvc:interceptors>
            
            
            <ref bean="firstInterceptor"></ref>
            <ref bean="secondInterceptor"></ref>
            
            
            
            
            
            
            
            
        </mvc:interceptors>
    </beans>

package com.qcw.interceptor;
    /**
     * @author wqc
     * @date 2022/10/3 15:02
     * Description:
     *  拦截器的三个方法：
     *   preHandle():在控制器方法执行之前执行，其返回值表示对控制器方法的拦截(false)或放行(true)
     *   postHandle():在控制器方法执行之后执行
     *   afterCompletion():在控制器方法执行之后，且渲染视图完毕后执行
     *
     *  多个拦截器的执行顺序 和在SpringMVC的配置文件中配置的顺序有关
     *   preHandle()按照配置的顺序执行，而postHandle()和afterCompletion()按照配置的反序执行
     *
     *  若拦截器中有某个拦截器的preHandle()返回了false
     *   拦截器的preHandle()返回false和它之前的拦截器的preHandle()都会执行
     *   所有的拦截器的postHandle()都不执行
     *   拦截器的preHandle()返回false之前的拦截器的afterCompletion()会执行
     */
    
    @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");
        }
    }

package com.qcw.interceptor;
    /**
     * @author wqc
     * @date 2022/10/3 18:45
     * Description:
     */
    
    @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");
        }
    }