Springboot2.6.x高版本与Swagger2版本冲突问题怎么解决

问题: 

Spring Boot 2.6.x版本引入依赖 springfox-boot-starter (Swagger 3.0) 后，启动容器会报错： 

Failed to start bean ‘ documentationPluginsBootstrapper ‘ ; nested exception… 

原因

Springfox 假设 Spring MVC 的路径匹配策略是 ant-path-matcher，而 Spring Boot 2.6.x版本的默认匹配策略是 path-pattern-matcher，这就造成了上面的报错。

完整解决方案:

1. pom配置

    org.springframework.boot
    spring-boot-starter-web
    2.6.4


    io.springfox
    springfox-boot-starter
    3.0.0

2. 添加Bean

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;
import org.springframework.stereotype.Component;
import org.springframework.util.ReflectionUtils;
import org.springframework.web.servlet.mvc.method.RequestMappingInfoHandlerMapping;
import springfox.documentation.spring.web.plugins.WebFluxRequestHandlerProvider;
import springfox.documentation.spring.web.plugins.WebMvcRequestHandlerProvider;
 
import java.lang.reflect.Field;
import java.util.List;
import java.util.stream.Collectors;
 
@Component
public class SwaggerBeanPostProcessor implements BeanPostProcessor {
    @Override
    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
        if (bean instanceof WebMvcRequestHandlerProvider || bean instanceof WebFluxRequestHandlerProvider)
        {
            List handlerMappings = getHandlerMappings(bean);
            customizeSpringfoxHandlerMappings(handlerMappings);
        }
        return bean;
    }
 
    private  void customizeSpringfoxHandlerMappings(List mappings) {
        List copy = mappings.stream()
                .filter(mapping -> mapping.getPatternParser() == null)
                .collect(Collectors.toList());
        mappings.clear();
        mappings.addAll(copy);
    }
    
    @SuppressWarnings("unchecked")
    private List getHandlerMappings(Object bean) {
        try {
            Field field = ReflectionUtils.findField(bean.getClass(), "handlerMappings");
            field.setAccessible(true);
            return (List) field.get(bean);
        }
        catch (IllegalArgumentException | IllegalAccessException e) {
            throw new IllegalStateException(e);
        }
    }
}

 3. swagger配置类继承 WebMvcConfigurationSupport

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport;
import springfox.documentation.service.ApiInfo;
import springfox.documentation.spi.DocumentationType;
import springfox.documentation.spring.web.plugins.Docket;
 
@Configuration
public class Swagger2Config extends WebMvcConfigurationSupport {
    @Bean
    public Docket createRestApi() {
        return new Docket(DocumentationType.SWAGGER_2)
                .apiInfo(ApiInfo.DEFAULT);
    }
 
    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.
                addResourceHandler("/swagger-ui/**")
                .addResourceLocations("classpath:/META-INF/resources/webjars/springfox-swagger-ui/")
                .resourceChain(false);
    }
}

 4. 访问 http://{ip}:{port}/swagger-ui/index.html