Spring Boot整合Swagger报错：“this.condition“ is null

分手后的思念是犯贱 2023-09-28 08:21 4阅读 0赞

前段时间看到群里有吐槽swagger整合问题，当时没仔细看，总以为是姿势不对。

这两天正好自己升级Spring Boot版本，然后突然出现了这样的一个错误：

Caused by: java.lang.NullPointerException: Cannot invoke "org.springframework.web.servlet.mvc.condition.PatternsRequestCondition.getPatterns()" because "this.condition" is null
        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$3(Orderings.java:89) ~[springfox-spi-3.0.0.jar:3.0.0]
        at java.base/java.util.Comparator.lambda$comparing$77a9974f$1(Comparator.java:473) ~[na:na]
        at java.base/java.util.TimSort.countRunAndMakeAscending(TimSort.java:355) ~[na:na]
        at java.base/java.util.TimSort.sort(TimSort.java:220) ~[na:na]
        at java.base/java.util.Arrays.sort(Arrays.java:1307) ~[na:na]
        at java.base/java.util.ArrayList.sort(ArrayList.java:1721) ~[na:na]
        at java.base/java.util.stream.SortedOps$RefSortingSink.end(SortedOps.java:392) ~[na:na]
        at java.base/java.util.stream.Sink$ChainedReference.end(Sink.java:258) ~[na:na]
        at java.base/java.util.stream.Sink$ChainedReference.end(Sink.java:258) ~[na:na]
        at java.base/java.util.stream.Sink$ChainedReference.end(Sink.java:258) ~[na:na]
        at java.base/java.util.stream.Sink$ChainedReference.end(Sink.java:258) ~[na:na]
        at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:510) ~[na:na]
        at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:499) ~[na:na]
        at java.base/java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:921) ~[na:na]
        at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) ~[na:na]
        at java.base/java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:682) ~[na:na]
        at springfox.documentation.spring.web.plugins.WebMvcRequestHandlerProvider.requestHandlers(WebMvcRequestHandlerProvider.java:81) ~[springfox-spring-webmvc-3.0.0.jar:3.0.0]
        at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:197) ~[na:na]
        at java.base/java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1625) ~[na:na]
        at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:509) ~[na:na]
        at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:499) ~[na:na]
        at java.base/java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:921) ~[na:na]
        at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) ~[na:na]
        at java.base/java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:682) ~[na:na]
        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-5.3.20.jar:5.3.20]
        ... 14 common frames omitted

查了一下，找到一个Spring Boot下的Issue：[https://github.com/spring-projects/spring-boot/issues/28794][https_github.com_spring-projects_spring-boot_issues_28794]，但这个issue已经关闭了，目前这个问题的主要讨论在springfox，具体issue是这个：[https://github.com/springfox/springfox/issues/3462][https_github.com_springfox_springfox_issues_3462]

![图 1][1]

![图 2][2]

顺着这个issue看了一下，这个问题主要出现在Spring Boot 2.6及以后，只要是Spring Boot 2.6引入的新PathPatternParser导致的。

目前从评论中得处的解决方案是：

1.  Path匹配策略切换回`ant_path_matcher`

spring.mvc.pathmatch.matching-strategy=ant_path_matcher

1.  添加下面这个Bean的定义

@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));
    }

我这边直接用了第一种方法，加了配置就好了。如果你最近也遇到这个问题，希望[这篇文章][Link 1]对你起到帮助！

本文首发：[Spring Boot整合Swagger时PatternsRequestCondition.getPatterns()报错："this.condition" is null][Link 1]，顺手推荐一个我正在连载的[Java新特性专栏][Java]，电子书形式编写，沉浸式阅读体验，赶紧加入收藏夹吧！

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[https_github.com_spring-projects_spring-boot_issues_28794]: https://github.com/spring-projects/spring-boot/issues/28794
[https_github.com_springfox_springfox_issues_3462]: https://github.com/springfox/springfox/issues/3462
[1]: https://img-blog.csdnimg.cn/ffc60d3e88764debbf0dc42e0a0402dc.png
[2]: https://img-blog.csdnimg.cn/6d4574d72c414a76a0dd9987645c1b5e.png
[Link 1]: https://blog.didispace.com/swagger-spring-boot-2-6/
[Java]: https://www.didispace.com/java-features/