Swagger之Failed to start bean ‘documentationPluginsBootstrapper‘； nested exception is java.lang

1、环境

win10、idea2020.1、JDK8、maven3.6、springboot2.6.2、swagger2.9.2

2、遇到问题

Failed to start bean 'documentationPluginsBootstrapper'; nested exception is java.lang.NullPointerException

原因：springboot 版本过高，使swagger 异常，或者说是引入的swagger版本过高导致的问题，或者说是springboot2.6.0更新以后引起的问题。

3、解决办法

方法1：在配置文件中下方代码：（推荐使用）：亲测springBoot2.6.2.、2.6.3、2.6.4有效

spring:
  mvc:
    pathmatch:
      matching-strategy: ant_path_matcher

方法2：修改springboot版本，原本springboot版本是 2.6.2改为下方2.5.7版本

 我使用的时候，并不理想，推荐使用方法1，如果想尝试方法2也可以试，我使用方法2提示如下图所示：希望我们使用2.6.x以上版本。

 使用方法1效果图：

 

 

附件：

觉得好的类似文章贴上：

链1：Swagger-Failed to start bean ‘documentationPluginsBootstrapper‘； nested exception is “空指针异常“

链2：Failed to start bean ‘documentationPluginsBootstrapper‘； nested exception is java.lang.NullPointerEx

链3：SpringFox3 Failed to start bean 'documentationPluginsBootstrapper'

链4：更详细配置请看这篇：Swagger（全） SpringBoot整合与使用_阿阿阿安的博客-CSDN博客_swagger整合spring

对上面的配置做出一点说明

具体报错

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2022-03-09 17:01:02.934 ERROR 25812 --- [  restartedMain] o.s.boot.SpringApplication               : 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) ~[spring-context-5.3.14.jar:5.3.14]
	at org.springframework.context.support.DefaultLifecycleProcessor.access$200(DefaultLifecycleProcessor.java:54) ~[spring-context-5.3.14.jar:5.3.14]
	at org.springframework.context.support.DefaultLifecycleProcessor$LifecycleGroup.start(DefaultLifecycleProcessor.java:356) ~[spring-context-5.3.14.jar:5.3.14]
	at java.lang.Iterable.forEach(Iterable.java:75) ~[na:1.8.0_311]
	at org.springframework.context.support.DefaultLifecycleProcessor.startBeans(DefaultLifecycleProcessor.java:155) ~[spring-context-5.3.14.jar:5.3.14]
	at org.springframework.context.support.DefaultLifecycleProcessor.onRefresh(DefaultLifecycleProcessor.java:123) ~[spring-context-5.3.14.jar:5.3.14]
	at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:935) ~[spring-context-5.3.14.jar:5.3.14]
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:586) ~[spring-context-5.3.14.jar:5.3.14]
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:145) ~[spring-boot-2.6.2.jar:2.6.2]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:730) [spring-boot-2.6.2.jar:2.6.2]
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:412) [spring-boot-2.6.2.jar:2.6.2]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:302) [spring-boot-2.6.2.jar:2.6.2]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1301) [spring-boot-2.6.2.jar:2.6.2]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1290) [spring-boot-2.6.2.jar:2.6.2]
	at com.nxg.upload.UploadServiceApplication.main(UploadServiceApplication.java:12) [classes/:na]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_311]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_311]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_311]
	at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_311]
	at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) [spring-boot-devtools-2.6.2.jar:2.6.2]
Caused by: java.lang.NullPointerException: null
	at springfox.documentation.spi.service.contexts.Orderings$8.compare(Orderings.java:112) ~[springfox-spi-2.9.2.jar:null]
	at springfox.documentation.spi.service.contexts.Orderings$8.compare(Orderings.java:109) ~[springfox-spi-2.9.2.jar:null]
	at com.google.common.collect.ComparatorOrdering.compare(ComparatorOrdering.java:37) ~[guava-20.0.jar:na]
	at java.util.TimSort.countRunAndMakeAscending(TimSort.java:355) ~[na:1.8.0_311]
	at java.util.TimSort.sort(TimSort.java:220) ~[na:1.8.0_311]
	at java.util.Arrays.sort(Arrays.java:1438) ~[na:1.8.0_311]
	at com.google.common.collect.Ordering.sortedCopy(Ordering.java:855) ~[guava-20.0.jar:na]
	at springfox.documentation.spring.web.plugins.WebMvcRequestHandlerProvider.requestHandlers(WebMvcRequestHandlerProvider.java:57) ~[springfox-spring-web-2.9.2.jar:null]
	at springfox.documentation.spring.web.plugins.DocumentationPluginsBootstrapper$2.apply(DocumentationPluginsBootstrapper.java:138) ~[springfox-spring-web-2.9.2.jar:null]
	at springfox.documentation.spring.web.plugins.DocumentationPluginsBootstrapper$2.apply(DocumentationPluginsBootstrapper.java:135) ~[springfox-spring-web-2.9.2.jar:null]
	at com.google.common.collect.Iterators$7.transform(Iterators.java:750) ~[guava-20.0.jar:na]
	at com.google.common.collect.TransformedIterator.next(TransformedIterator.java:47) ~[guava-20.0.jar:na]
	at com.google.common.collect.TransformedIterator.next(TransformedIterator.java:47) ~[guava-20.0.jar:na]
	at com.google.common.collect.MultitransformedIterator.hasNext(MultitransformedIterator.java:52) ~[guava-20.0.jar:na]
	at com.google.common.collect.MultitransformedIterator.hasNext(MultitransformedIterator.java:50) ~[guava-20.0.jar:na]
	at com.google.common.collect.ImmutableList.copyOf(ImmutableList.java:249) ~[guava-20.0.jar:na]
	at com.google.common.collect.ImmutableList.copyOf(ImmutableList.java:209) ~[guava-20.0.jar:na]
	at com.google.common.collect.FluentIterable.toList(FluentIterable.java:614) ~[guava-20.0.jar:na]
	at springfox.documentation.spring.web.plugins.DocumentationPluginsBootstrapper.defaultContextBuilder(DocumentationPluginsBootstrapper.java:111) ~[springfox-spring-web-2.9.2.jar:null]
	at springfox.documentation.spring.web.plugins.DocumentationPluginsBootstrapper.buildContext(DocumentationPluginsBootstrapper.java:96) ~[springfox-spring-web-2.9.2.jar:null]
	at springfox.documentation.spring.web.plugins.DocumentationPluginsBootstrapper.start(DocumentationPluginsBootstrapper.java:167) ~[springfox-spring-web-2.9.2.jar:null]
	at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:178) ~[spring-context-5.3.14.jar:5.3.14]
	... 19 common frames omitted


Process finished with exit code 0