【后端】【Java】Swagger 与 Spring Boot 2.6+ 版本不兼容的问题

Spring Boot 2.6+ 修改了路径匹配策略，导致 Springfox Swagger 3.0.0 出现空指针异常，启动后报错如下所示：

2025-12-16 00:00:56 [main] INFO o.a.catalina.core.StandardService - Stopping service [Tomcat] 2025-12-16 00:00:56 [main] INFO o.s.b.a.l.ConditionEvaluationReportLoggingListener - Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled. 2025-12-16 00:00:56 [main] ERROR o.s.boot.SpringApplication - Application run failed org.springframework.context.ApplicationContextException: Failed to start bean 'documentationPluginsBootstrapper'; nested exception is java.lang.NullPointerException: Cannot invoke "org.springframework.web.servlet.mvc.condition.PatternsRequestCondition.getPatterns()" because "this.condition" is null 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:937) 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:745) at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:423) at org.springframework.boot.SpringApplication.run(SpringApplication.java:307) at org.springframework.boot.SpringApplication.run(SpringApplication.java:1317) at org.springframework.boot.SpringApplication.run(SpringApplication.java:1306) at com.example.chapter05.Chapter05Application.main(Chapter05Application.java:13) 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) at springfox.documentation.RequestHandler.sortedPaths(RequestHandler.java:113) at springfox.documentation.spi.service.contexts.Orderings.lambda$byPatternsCondition$3(Orderings.java:89) at java.base/java.util.Comparator.lambda$comparing$77a9974f$1(Comparator.java:473) at java.base/java.util.TimSort.countRunAndMakeAscending(TimSort.java:355) at java.base/java.util.TimSort.sort(TimSort.java:220) at java.base/java.util.Arrays.sort(Arrays.java:1307) at java.base/java.util.ArrayList.sort(ArrayList.java:1721) at java.base/java.util.stream.SortedOps$RefSortingSink.end(SortedOps.java:392) at java.base/java.util.stream.Sink$ChainedReference.end(Sink.java:258) at java.base/java.util.stream.Sink$ChainedReference.end(Sink.java:258) at java.base/java.util.stream.Sink$ChainedReference.end(Sink.java:258) at java.base/java.util.stream.Sink$ChainedReference.end(Sink.java:258) at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:510) at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:499) at java.base/java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:921) at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) at java.base/java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:682) at springfox.documentation.spring.web.plugins.WebMvcRequestHandlerProvider.requestHandlers(WebMvcRequestHandlerProvider.java:81) at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:197) at java.base/java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1625) at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:509) at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:499) at java.base/java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:921) at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) at java.base/java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:682) at springfox.documentation.spring.web.plugins.AbstractDocumentationPluginsBootstrapper.withDefaults(AbstractDocumentationPluginsBootstrapper.java:107) at springfox.documentation.spring.web.plugins.AbstractDocumentationPluginsBootstrapper.buildContext(AbstractDocumentationPluginsBootstrapper.java:91) at springfox.documentation.spring.web.plugins.AbstractDocumentationPluginsBootstrapper.bootstrapDocumentationPlugins(AbstractDocumentationPluginsBootstrapper.java:82) at springfox.documentation.spring.web.plugins.DocumentationPluginsBootstrapper.start(DocumentationPluginsBootstrapper.java:100) at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:178) ... 14 common frames omitted

✅修复方案：

在 application.yml 中添加了以下配置：

spring: mvc: pathmatch: matching-strategy: ant_path_matcher

📝 问题说明

原因：

• Spring Boot 2.6+ 默认使用 PathPatternParser作为路径匹配策略
• Springfox Swagger 3.0.0 仍然使用旧的 AntPathMatcher
• 两者不兼容导致空指针异常

解决办法：
将 Spring MVC 的路径匹配策略改回 ant_path_matcher，使其与 Swagger 兼容。

🚀 现在可以重新启动应用

重启 Chapter05Application 后：
- 应用将正常启动
- Swagger UI 可访问：http://localhost:8080/swagger-ui/
- 所有 RESTful 接口正常工作

如果您不需要 Swagger 文档功能，也可以选择删除 Swagger 相关依赖和配置类。