在最新的SpringBoot2.6中使用Swagger，引入springfox-swagger2后（版本2.9.2），啟動項目報無法加載documentationPluginsBootstrapper：
ERROR [main][org.springframework.boot.SpringApplication]:819 - Application run failed
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)
at org.springframework.context.support.DefaultLifecycleProcessor.access$200(DefaultLifecycleProcessor.java:54)
at org.springframework.context.support.DefaultLifecycleProcessor$LifecycleGroup.start(DefaultLifecycleProcessor.java:356)
at java.base/java.lang.Iterable.forEach(Iterable.java:75)
at org.springframework.context.support.DefaultLifecycleProcessor.startBeans(DefaultLifecycleProcessor.java:155)
at org.springframework.context.support.DefaultLifecycleProcessor.onRefresh(DefaultLifecycleProcessor.java:123)
at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:935)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:586)
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:145)
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:730)
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:412)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:302)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1301)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1290)
at com.ikang.mis.sms.MisSmsApplication.main(MisSmsApplication.java:10)
Caused by: java.lang.NullPointerException: null
at springfox.documentation.spi.service.contexts.Orderings$8.compare(Orderings.java:112)
at springfox.documentation.spi.service.contexts.Orderings$8.compare(Orderings.java:109)
at com.google.common.collect.ComparatorOrdering.compare(ComparatorOrdering.java:37)
at java.base/java.util.TimSort.countRunAndMakeAscending(TimSort.java:355)
at java.base/java.util.TimSort.sort(TimSort.java:220)
at java.base/java.util.Arrays.sort(Arrays.java:1442)
at com.google.common.collect.Ordering.sortedCopy(Ordering.java:855)
at springfox.documentation.spring.web.plugins.WebMvcRequestHandlerProvider.requestHandlers(WebMvcRequestHandlerProvider.java:57)
at springfox.documentation.spring.web.plugins.DocumentationPluginsBootstrapper$2.apply(DocumentationPluginsBootstrapper.java:138)
at springfox.documentation.spring.web.plugins.DocumentationPluginsBootstrapper$2.apply(DocumentationPluginsBootstrapper.java:135)
at com.google.common.collect.Iterators$7.transform(Iterators.java:750)
at com.google.common.collect.TransformedIterator.next(TransformedIterator.java:47)
at com.google.common.collect.TransformedIterator.next(TransformedIterator.java:47)
at com.google.common.collect.MultitransformedIterator.hasNext(MultitransformedIterator.java:52)
at com.google.common.collect.MultitransformedIterator.hasNext(MultitransformedIterator.java:50)
at com.google.common.collect.ImmutableList.copyOf(ImmutableList.java:249)
at com.google.common.collect.ImmutableList.copyOf(ImmutableList.java:209)
at com.google.common.collect.FluentIterable.toList(FluentIterable.java:614)
at springfox.documentation.spring.web.plugins.DocumentationPluginsBootstrapper.defaultContextBuilder(DocumentationPluginsBootstrapper.java:111)
at springfox.documentation.spring.web.plugins.DocumentationPluginsBootstrapper.buildContext(DocumentationPluginsBootstrapper.java:96)
at springfox.documentation.spring.web.plugins.DocumentationPluginsBootstrapper.start(DocumentationPluginsBootstrapper.java:167)
at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:178)
... 14 common frames omitted
Process finished with exit code 1
出現以上錯誤，是由Springfox的一個bug引起的，這是在假設SpringMVC是如何建立的，但這並不總是成立的。具體來說，它假設MVC的路徑匹配將使用基於Ant-based的路徑匹配器，而不是基於PathPattern-based的匹配器。基於PathPattern-based的匹配已經是一個選項，並且是SpringBoot2.6的默認選項。
如Spring Boot 2.6發行說明中所述，您可以通過在application.properties文件中將Spring.mvc.pathmatch.matching-strategy設置為ant path matcher來恢復Springfox假定將使用的配置。請注意，只有在不使用Spring Boot的執行器時，此功能才起作用。無論配置的匹配策略如何，執行器始終使用基於路徑模式的解析。如果您想在Spring Boot 2.6及更高版本中將其與執行器一起使用，則需要對Springfox進行更改。