解决springboot2.6和swagger冲突的四种方法

最近要将后台服务从SpringBoot1升级到2版本，主要目的是为了使用SpringBoot2的实时监控功能。集成的时候无法启动，根据日志判断与swagger有关。查了半天，一个解释是springboot修改了请求路由匹配策略，Spring MVC 处理程序映射匹配请求路径的默认策略已从 AntPathMatcher 更改为PathPatternParser。Actuator端点现在也使用基于 P

纵横千里，捭阖四方

5585人浏览 · 2022-09-28 16:21:16

纵横千里，捭阖四方 · 2022-09-28 16:21:16 发布

最近要将后台服务从SpringBoot1升级到2版本，主要目的是为了使用SpringBoot2的实时监控功能。集成的时候无法启动，根据日志判断与swagger有关。信息如下：

org.springframework.context.ApplicationContextException: Failed to start bean 'documentationPluginsBootstrapper'; nested exception is java.lang.NullPointerException
	at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:181) ~[spring-context-5.3.13.jar:5.3.13]
	at org.springframework.context.support.DefaultLifecycleProcessor.access$200(DefaultLifecycleProcessor.java:54) ~[spring-context-5.3.13.jar:5.3.13]
	at org.springframework.context.support.DefaultLifecycleProcessor$LifecycleGroup.start(DefaultLifecycleProcessor.java:356) ~[spring-context-5.3.13.jar:5.3.13]
	at java.lang.Iterable.forEach(Iterable.java:75) ~[?:?]
	at org.springframework.context.support.DefaultLifecycleProcessor.startBeans(DefaultLifecycleProcessor.java:155) ~[spring-context-5.3.13.jar:5.3.13]
	at org.springframework.context.support.DefaultLifecycleProcessor.onRefresh(DefaultLifecycleProcessor.java:123) ~[spring-context-5.3.13.jar:5.3.13]
	at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:935) ~[spring-context-5.3.13.jar:5.3.13]
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:586) ~[spring-context-5.3.13.jar:5.3.13]
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:145) ~[spring-boot-2.6.1.jar:2.6.1]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:730) ~[spring-boot-2.6.1.jar:2.6.1]
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:412) ~[spring-boot-2.6.1.jar:2.6.1]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:302) ~[spring-boot-2.6.1.jar:2.6.1]
	at com.iscas.biz.BizApp.main(BizApp.java:69) ~[classes/:?]
Caused by: java.lang.NullPointerException
	at springfox.documentation.spring.web.WebMvcPatternsRequestConditionWrapper.getPatterns(WebMvcPatternsRequestConditionWrapper.java:56) ~[springfox-spring-webmvc-3.0.0.jar:3.0.0]
	at springfox.documentation.RequestHandler.sortedPaths(RequestHandler.java:113) ~[springfox-core-3.0.0.jar:3.0.0]
	at springfox.documentation.spi.service.contexts.Orderings.lambda$byPatternsCondition$3(Orderings.java:89) ~[springfox-spi-3.0.0.jar:3.0.0]
	at java.util.Comparator.lambda$comparing$77a9974f$1(Comparator.java:469) ~[?:?]
	at java.util.TimSort.countRunAndMakeAscending(TimSort.java:355) ~[?:?]
	at java.util.TimSort.sort(TimSort.java:234) ~[?:?]
	at java.util.Arrays.sort(Arrays.java:1515) ~[?:?]
	at java.util.ArrayList.sort(ArrayList.java:1750) ~[?:?]
	at java.util.stream.SortedOps$RefSortingSink.end(SortedOps.java:392) ~[?:?]
	at java.util.stream.Sink$ChainedReference.end(Sink.java:258) ~[?:?]
	at java.util.stream.Sink$ChainedReference.end(Sink.java:258) ~[?:?]
	at java.util.stream.Sink$ChainedReference.end(Sink.java:258) ~[?:?]
	at java.util.stream.Sink$ChainedReference.end(Sink.java:258) ~[?:?]
	at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:485) ~[?:?]
	at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474) ~[?:?]
	at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:913) ~[?:?]
	at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) ~[?:?]
	at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:578) ~[?:?]
	at springfox.documentation.spring.web.plugins.WebMvcRequestHandlerProvider.requestHandlers(WebMvcRequestHandlerProvider.java:81) ~[springfox-spring-webmvc-3.0.0.jar:3.0.0]
	at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:195) ~[?:?]
	at java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1655) ~[?:?]
	at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484) ~[?:?]
	at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474) ~[?:?]
	at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:913) ~[?:?]
	at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) ~[?:?]
	at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:578) ~[?:?]
	at springfox.documentation.spring.web.plugins.AbstractDocumentationPluginsBootstrapper.withDefaults(AbstractDocumentationPluginsBootstrapper.java:107) ~[springfox-spring-web-3.0.0.jar:3.0.0]
	at springfox.documentation.spring.web.plugins.AbstractDocumentationPluginsBootstrapper.buildContext(AbstractDocumentationPluginsBootstrapper.java:91) ~[springfox-spring-web-3.0.0.jar:3.0.0]
	at springfox.documentation.spring.web.plugins.AbstractDocumentationPluginsBootstrapper.bootstrapDocumentationPlugins(AbstractDocumentationPluginsBootstrapper.java:82) ~[springfox-spring-web-3.0.0.jar:3.0.0]
	at springfox.documentation.spring.web.plugins.DocumentationPluginsBootstrapper.start(DocumentationPluginsBootstrapper.java:100) ~[springfox-spring-web-3.0.0.jar:3.0.0]
	at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:178) ~[spring-context-5.3.13.jar:5.3.13]
	... 12 more

查了半天，一个解释是springboot修改了请求路由匹配策略，

Spring MVC 处理程序映射匹配请求路径的默认策略已从 AntPathMatcher 更改为PathPatternParser。Actuator端点现在也使用基于 PathPattern 的 URL 匹配，因此Actuator端点的路径匹配策略无法通过配置属性进行配置。

我采用的方法

如果需要将默认切换回 AntPathMatcher，可以将 spring.mvc.pathmatch.matching-strategy 设置为 ant-path-matcher，比如下面这样：

spring.mvc.pathmatch.matching-strategy=ant-path-matcher

一种解决办法是手动创建一个配置类，来修改路由规则，在你工程创建一个包：

springfox.documentation.spring.web.plugins

注意这里必须使用上面的包名，这样才能代替springfox自带的。

然后创建一个类，完整代码如下：

/**
 * springboot升级到2.6后和swagger出现冲突，这是springboot修改了请求路由匹配策略造成的。
 * Spring MVC 处理程序映射匹配请求路径的默认策略已从 AntPathMatcher 更改为PathPatternParser，导致swagger加载失败，
 * 这里手动设置一下
 */

package springfox.documentation.spring.web.plugins;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.mvc.method.RequestMappingInfo;
import org.springframework.web.servlet.mvc.method.RequestMappingInfoHandlerMapping;
import springfox.documentation.RequestHandler;
import springfox.documentation.builders.BuilderDefaults;
import springfox.documentation.spi.service.RequestHandlerProvider;
import springfox.documentation.spi.service.contexts.Orderings;
import springfox.documentation.spring.web.WebMvcRequestHandler;
import springfox.documentation.spring.web.readers.operation.HandlerMethodResolver;

import javax.servlet.ServletContext;
import java.util.List;
import java.util.Map.Entry;
import java.util.Objects;
import java.util.Optional;
import java.util.function.Function;
import java.util.stream.Collectors;
import java.util.stream.StreamSupport;

import static springfox.documentation.spring.web.paths.Paths.ROOT;

@Component
@Order(-2147483648)
public class WebMvcRequestHandlerProvider implements RequestHandlerProvider {
    private final List<RequestMappingInfoHandlerMapping> handlerMappings;
    private final HandlerMethodResolver methodResolver;
    private final String contextPath;

    @Autowired
    public WebMvcRequestHandlerProvider(Optional<ServletContext> servletContext, HandlerMethodResolver methodResolver, List<RequestMappingInfoHandlerMapping> handlerMappings) {
        this.handlerMappings = handlerMappings.stream().filter(mapping -> Objects.isNull(mapping.getPatternParser())).collect(Collectors.toList());
        this.methodResolver = methodResolver;
        this.contextPath = servletContext
                .map(ServletContext::getContextPath)
                .orElse(ROOT);
    }

    public List<RequestHandler> requestHandlers() {
        return (List)BuilderDefaults.nullToEmptyList(this.handlerMappings).stream().filter((requestMappingInfoHandlerMapping) -> {
            return !"org.springframework.integration.http.inbound.IntegrationRequestMappingHandlerMapping".equals(requestMappingInfoHandlerMapping.getClass().getName());
        }).map(this.toMappingEntries()).flatMap((entries) -> {
            return StreamSupport.stream(entries.spliterator(), false);
        }).map(this.toRequestHandler()).sorted(Orderings.byPatternsCondition()).collect(Collectors.toList());
    }

    private Function<RequestMappingInfoHandlerMapping, Iterable<Entry<RequestMappingInfo, HandlerMethod>>> toMappingEntries() {
        return (input) -> {
            return input.getHandlerMethods().entrySet();
        };
    }

    private Function<Entry<RequestMappingInfo, HandlerMethod>, RequestHandler> toRequestHandler() {
        return (input) -> {
            return new WebMvcRequestHandler(this.contextPath, this.methodResolver, (RequestMappingInfo)input.getKey(), (HandlerMethod)input.getValue());
        };
    }
}

上面代码的核心是修改了构造器的实现代码，你可以与原始的对照一下，就是把不符合规则的控制器过滤器掉了。

这样就能解决问题了。

网上还有人说这样解决不优雅，其他的方式没有使用，这里一起附上，供你参考：

第二种参考方法

添加一个BeanPostProcessor，在postProcessAfterInitialization中修改WebMvcRequestHandlerProvider中的handlerMappings属性，这种方式其实更第一种是一样的，这样不用覆盖原有类，更优雅一些。

package com.iscas.biz.config;

/**
 * 自定义BeanPostProcessor
 *
 * @author zhuquanwen
 * @version 1.0
 * @date 2021/12/29
 * @since jdk11/
 */
@SuppressWarnings({"unused", "unchecked"})
@Component
@Slf4j
public class MyBeanPostProcessor implements BeanPostProcessor {
    @Autowired
    private DefaultListableBeanFactory defaultListableBeanFactory;

    @Override
    public Object postProcessBeforeInitialization(@NotNull Object bean, @NotNull String beanName) throws BeansException {
        return bean;
    }

    @Override
    public Object postProcessAfterInitialization(@NotNull Object bean, @NotNull String beanName) throws BeansException {
        handleWebMvcRequestHandlerProvider(beanName, bean);
        return bean;
    }

    private void handleWebMvcRequestHandlerProvider(String beanName, Object bean) {
        // 处理swagger 在spring boot2.6以上不可用的问题
        boolean modify = (bean instanceof WebMvcRequestHandlerProvider || bean instanceof WebFluxRequestHandlerProvider) &&
                defaultListableBeanFactory.containsBean(beanName);
        if (modify) {
            // 修改属性
            try {
                Field handlerMappingsField = bean.getClass().getDeclaredField("handlerMappings");
                ReflectUtils.makeAccessible(handlerMappingsField);
                List<RequestMappingInfoHandlerMapping> handlerMappings = (List<RequestMappingInfoHandlerMapping>) handlerMappingsField.get(bean);
                List<RequestMappingInfoHandlerMapping> tmpHandlerMappings = handlerMappings.stream().filter(mapping -> Objects.isNull(mapping.getPatternParser())).collect(Collectors.toList());
                handlerMappings.clear();
                handlerMappings.addAll(tmpHandlerMappings);
            } catch (Exception e) {
                log.warn("修改WebMvcRequestHandlerProvider的属性：handlerMappings出错，可能导致swagger不可用", e);
            }
        }
    }
}

ReflectUtils.makeAccessible的方法：

    public static void makeAccessible(Field field) {
        if ((!Modifier.isPublic(field.getModifiers()) ||
                !Modifier.isPublic(field.getDeclaringClass().getModifiers()) ||
                Modifier.isFinal(field.getModifiers())) && !field.isAccessible()) {
            field.setAccessible(true);
        }
    }

第三种解决办法

这种是最优雅的方式，我测试时发现并没有生效，暂且一起附上吧，希望对你有用：

注册一个WebMvcEndpointHandlerMapping类。

@Bean
    public WebMvcEndpointHandlerMapping webEndpointServletHandlerMapping(WebEndpointsSupplier webEndpointsSupplier,
                                                                         ServletEndpointsSupplier servletEndpointsSupplier,
                                                                         ControllerEndpointsSupplier controllerEndpointsSupplier,
                                                                         EndpointMediaTypes endpointMediaTypes,
                                                                         CorsEndpointProperties corsProperties,
                                                                         WebEndpointProperties webEndpointProperties,
                                                                         Environment environment) {
        List<ExposableEndpoint<?>> allEndpoints = new ArrayList<>();
        Collection<ExposableWebEndpoint> webEndpoints = webEndpointsSupplier.getEndpoints();
        allEndpoints.addAll(webEndpoints);
        allEndpoints.addAll(servletEndpointsSupplier.getEndpoints());
        allEndpoints.addAll(controllerEndpointsSupplier.getEndpoints());
        String basePath = webEndpointProperties.getBasePath();
        EndpointMapping endpointMapping = new EndpointMapping(basePath);
        boolean shouldRegisterLinksMapping = this.shouldRegisterLinksMapping(webEndpointProperties, environment, basePath);
        return new WebMvcEndpointHandlerMapping(endpointMapping, webEndpoints, endpointMediaTypes, corsProperties.toCorsConfiguration(),
                new EndpointLinksResolver(allEndpoints, basePath), shouldRegisterLinksMapping, null);
    }

    private boolean shouldRegisterLinksMapping(WebEndpointProperties webEndpointProperties, Environment environment, String basePath) {

        return webEndpointProperties.getDiscovery().isEnabled() && (StringUtils.hasText(basePath) ||
                ManagementPortType.get(environment).equals(ManagementPortType.DIFFERENT));

    }

之后在另外一个工程又遇到了类似的情况，但是上面的三种都不好使，所以又找到了第四种解决方法：

第四种方法

在你的工程里创建一个配置类，内容如下：

package com.fenbi.im.service.config;

import org.springframework.boot.actuate.autoconfigure.endpoint.web.CorsEndpointProperties;
import org.springframework.boot.actuate.autoconfigure.endpoint.web.WebEndpointProperties;
import org.springframework.boot.actuate.autoconfigure.web.server.ManagementPortType;
import org.springframework.boot.actuate.endpoint.ExposableEndpoint;
import org.springframework.boot.actuate.endpoint.web.*;
import org.springframework.boot.actuate.endpoint.web.annotation.ControllerEndpointsSupplier;
import org.springframework.boot.actuate.endpoint.web.annotation.ServletEndpointsSupplier;
import org.springframework.boot.actuate.endpoint.web.servlet.WebMvcEndpointHandlerMapping;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.env.Environment;
import org.springframework.util.StringUtils;
import org.springframework.web.bind.annotation.RestController;
import springfox.documentation.builders.ApiInfoBuilder;
import springfox.documentation.builders.PathSelectors;
import springfox.documentation.builders.RequestHandlerSelectors;
import springfox.documentation.service.ApiInfo;
import springfox.documentation.service.Contact;
import springfox.documentation.spi.DocumentationType;
import springfox.documentation.spring.web.plugins.Docket;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

/***
 * @date 2022/10/26
 * author https://blog.csdn.net/xueyushenzhou?type=blog
 */
@Configuration
public class SpringFoxSwaggerConfig {
    /**
     * 配置基本信息
     *
     * @return
     */
    @Bean
    public ApiInfo apiInfo() {
        return new ApiInfoBuilder()
                .title("Swagger Test App Restful API")
                .description("swagger test app restful api")
                .termsOfServiceUrl("test")
                .contact(new Contact("haha", "https://blog.csdn.net/xueyushenzhou?type=blog", "abc@hotmail.com"))
                .version("1.0")
                .build();
    }

    /**
     * 配置文档生成最佳实践
     *
     * @param apiInfo
     * @return
     */
    @Bean
    public Docket createRestApi(ApiInfo apiInfo) {
        return new Docket(DocumentationType.SWAGGER_2)
                .apiInfo(apiInfo)
                .groupName("SwaggerGroupOneAPI")
                .select()
                .apis(RequestHandlerSelectors.withClassAnnotation(RestController.class))
                .paths(PathSelectors.any())
                .build();
    }

    /**
     * 增加如下配置可解决Spring Boot 6.x 与Swagger 3.0.0 不兼容问题
     **/
    @Bean
    public WebMvcEndpointHandlerMapping webEndpointServletHandlerMapping(WebEndpointsSupplier webEndpointsSupplier, ServletEndpointsSupplier servletEndpointsSupplier, ControllerEndpointsSupplier controllerEndpointsSupplier, EndpointMediaTypes endpointMediaTypes, CorsEndpointProperties corsProperties, WebEndpointProperties webEndpointProperties, Environment environment) {
        List<ExposableEndpoint<?>> allEndpoints = new ArrayList();
        Collection<ExposableWebEndpoint> webEndpoints = webEndpointsSupplier.getEndpoints();
        allEndpoints.addAll(webEndpoints);
        allEndpoints.addAll(servletEndpointsSupplier.getEndpoints());
        allEndpoints.addAll(controllerEndpointsSupplier.getEndpoints());
        String basePath = webEndpointProperties.getBasePath();
        EndpointMapping endpointMapping = new EndpointMapping(basePath);
        boolean shouldRegisterLinksMapping = this.shouldRegisterLinksMapping(webEndpointProperties, environment, basePath);
        return new WebMvcEndpointHandlerMapping(endpointMapping, webEndpoints, endpointMediaTypes, corsProperties.toCorsConfiguration(), new EndpointLinksResolver(allEndpoints, basePath), shouldRegisterLinksMapping, null);
    }

    private boolean shouldRegisterLinksMapping(WebEndpointProperties webEndpointProperties, Environment environment, String basePath) {
        return webEndpointProperties.getDiscovery().isEnabled() && (StringUtils.hasText(basePath) || ManagementPortType.get(environment).equals(ManagementPortType.DIFFERENT));
    }
}

这样也能解决，懒得研究原理，干脆都记下吧

祝你顺利！