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Spring Boot 2(Spring 5.0+) HandlerInterceptor 拦截器简单示例

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1 摘要

拦截器在 Web 项目中发挥着重要的作用，其可以帮助应用过滤掉无效的请求。Spring Boot 中拦截器的实现方式主要有两种，一种是通过实现 javax.servlet.Filter 接口，这一种方式是传统的拦截器，能够实现的功能较少；另一种是使用 Spring 框架的拦截器，实现 org.springframework.web.servlet.HandlerInterceptor 接口。本文将介绍通过Spring Boot 2.X(Spring 5.X) HandlerInterceptor 拦截器的简单应用。

Filter 拦截器可参考:

22.SpringBoot 项目之前端跨域终结者—2019-05-23

2 核心 Maven 依赖

../pom.xml
../demo-web/pom.xml

            <!-- web,mvc -->
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
                <version>${springboot.version}</version>
            </dependency>

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3 核心代码

3.1 拦截器类

../demo-web/src/main/java/com/ljq/demo/springboot/web/acpect/SimpleInterceptor.java

package com.ljq.demo.springboot.web.acpect;

import lombok.extern.slf4j.Slf4j;
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;

/**
 * @Description: 简易拦截器应用
 * @Author: junqiang.lu
 * @Date: 2019/12/10
 */
@Slf4j
@Component
public class SimpleInterceptor implements HandlerInterceptor {


    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        log.info("preHandle");
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        log.info("postHandle");

    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        log.info("afterCompletion");
        log.info("Content-Type: {}", response.getHeader("Content-Type"));

    }
}

方法说明:

prehandle() : 该方法在拦截器执行之前执行，此时返回视图未生成

postHandle() : 拦截器执行方法

afterCompletion() : 请求处理完成之后,此时返回视图已经生成

3.2 拦截器配置类

../demo-web/src/main/java/com/ljq/demo/springboot/web/acpect/MvcConfig.java

package com.ljq.demo.springboot.web.acpect;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.config.annotation.CorsRegistry;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

/**
 * @Description: wed mvc 配置信息
 * @Author: junqiang.lu
 * @Date: 2019/12/10
 */
@Component
public class MvcConfig implements WebMvcConfigurer {

    @Autowired
    private SimpleInterceptor simpleInterceptor;

    /**
     * 指定拦截器
     *
     * @param registry
     */
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(simpleInterceptor)
                .addPathPatterns("/**")
                .excludePathPatterns("/swagger-resources/**", "/webjars/**", "/v2/**", "/swagger-ui.html/**");
    }

    /**
     * 资源过滤
     *
     * @param registry
     */
    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("swagger-ui.html")
                .addResourceLocations("classpath:/META-INF/resources/");
        registry.addResourceHandler("/webjars/**")
                .addResourceLocations("classpath:/META-INF/resources/webjars/");
    }

    /**
     * 跨域处理
     *
     * @param registry
     */
    @Override
    public void addCorsMappings(CorsRegistry registry) {
        registry.addMapping("/**")
                .allowedMethods("GET","HEAD","POST","PUT","PATCH","DELETE","OPTIONS","TRACE")
                .allowedOrigins("*")
                .allowedHeaders("*")
                .maxAge(3600);

    }
}

​

4 参考资料推荐

Introduction to Spring MVC HandlerInterceptor

Spring Boot - Interceptor

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5 本次提交记录

commit 4e32a9543e692ad8e10254a26ce3fbb5154c136f
Author: flying9001 <flying9001@gmail.com>
Date:   Tue Dec 10 16:34:32 2019 +0800

    代码-新增 Spring Boot 2(Spring 5.0+) HandlerInterceptor 拦截器简单示例

版本回退命令:

git reset --soft 4e32a9543e692ad8e10254a26ce3fbb5154c136f