项目场景：

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

问题描述

springboot 集成Swagger2报错

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) ~[na:1.8.0_281]
	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 org.springframework.boot.SpringApplication.run(SpringApplication.java:1301) [spring-boot-2.6.1.jar:2.6.1]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1290) [spring-boot-2.6.1.jar:2.6.1]
	at com.zstudyj.ApiApplication.main(ApiApplication.java:12) [classes/:na]
Caused by: java.lang.NullPointerException: null
	at springfox.documentation.spi.service.contexts.Orderings$8.compare(Orderings.java:113) ~[springfox-spi-2.7.0.jar:2.7.0]
	at springfox.documentation.spi.service.contexts.Orderings$8.compare(Orderings.java:110) ~[springfox-spi-2.7.0.jar:2.7.0]
	at com.google.common.collect.ComparatorOrdering.compare(ComparatorOrdering.java:38) ~[guava-18.0.jar:na]
	at java.util.TimSort.countRunAndMakeAscending(TimSort.java:355) ~[na:1.8.0_281]
	at java.util.TimSort.sort(TimSort.java:220) ~[na:1.8.0_281]
	at java.util.Arrays.sort(Arrays.java:1438) ~[na:1.8.0_281]
	at com.google.common.collect.Ordering.sortedCopy(Ordering.java:817) ~[guava-18.0.jar:na]
	at springfox.documentation.spring.web.plugins.WebMvcRequestHandlerProvider.requestHandlers(WebMvcRequestHandlerProvider.java:52) ~[springfox-spring-web-2.7.0.jar:2.7.0]
	at springfox.documentation.spring.web.plugins.DocumentationPluginsBootstrapper$2.apply(DocumentationPluginsBootstrapper.java:129) ~[springfox-spring-web-2.7.0.jar:2.7.0]
	at springfox.documentation.spring.web.plugins.DocumentationPluginsBootstrapper$2.apply(DocumentationPluginsBootstrapper.java:126) ~[springfox-spring-web-2.7.0.jar:2.7.0]
	at com.google.common.collect.Iterators$8.transform(Iterators.java:799) ~[guava-18.0.jar:na]
	at com.google.common.collect.TransformedIterator.next(TransformedIterator.java:48) ~[guava-18.0.jar:na]
	at com.google.common.collect.TransformedIterator.next(TransformedIterator.java:48) ~[guava-18.0.jar:na]
	at com.google.common.collect.Iterators$5.hasNext(Iterators.java:548) ~[guava-18.0.jar:na]
	at com.google.common.collect.ImmutableList.copyOf(ImmutableList.java:268) ~[guava-18.0.jar:na]
	at com.google.common.collect.ImmutableList.copyOf(ImmutableList.java:226) ~[guava-18.0.jar:na]
	at com.google.common.collect.FluentIterable.toList(FluentIterable.java:373) ~[guava-18.0.jar:na]
	at springfox.documentation.spring.web.plugins.DocumentationPluginsBootstrapper.defaultContextBuilder(DocumentationPluginsBootstrapper.java:100) ~[springfox-spring-web-2.7.0.jar:2.7.0]
	at springfox.documentation.spring.web.plugins.DocumentationPluginsBootstrapper.buildContext(DocumentationPluginsBootstrapper.java:91) ~[springfox-spring-web-2.7.0.jar:2.7.0]
	at springfox.documentation.spring.web.plugins.DocumentationPluginsBootstrapper.start(DocumentationPluginsBootstrapper.java:154) ~[springfox-spring-web-2.7.0.jar:2.7.0]
	at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:178) ~[spring-context-5.3.13.jar:5.3.13]
	... 14 common frames omitted


Process finished with exit code 1

原因分析：

Springboot2.6以后将SpringMVC 默认路径匹配策略从AntPathMatcher 更改为PathPatternParser，导致出错

解决方案：

在配置文件application.properties中加入以下配置

spring.mvc.pathmatch.matching-strategy=ANT_PATH_MATCHER