Springfox 3.0.0 不适用于 Spring Boot 2.6.0答案

【问题标题】：Springfox 3.0.0 is not working with Spring Boot 2.6.0 [duplicate]Springfox 3.0.0 不适用于 Spring Boot 2.6.0
【发布时间】：2022-01-07 16:45:57
【问题描述】：

Springfox 3.0.0 不适用于 Spring Boot 2.6.0，升级后出现以下错误

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: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.enkindle.AntivirusApplication.main(AntivirusApplication.java:16)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:568)
    at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49)
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$1(Comparator.java:473)
    at java.base/java.util.TimSort.countRunAndMakeAscending(TimSort.java:355)
    at java.base/java.util.TimSort.sort(TimSort.java:234)
    at java.base/java.util.Arrays.sort(Arrays.java:1307)
    at java.base/java.util.ArrayList.sort(ArrayList.java:1721)
    at java.base/java.util.stream.SortedOps$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)
    ... 19 common frames omitted

【问题讨论】：

SpringBoot 2.6.1 也有这个问题（springfox-boot-starter 3.0.0）

标签： java spring-boot swagger springfox spring-boot-2.6.0

【解决方案1】：

我知道这并不能直接解决您的问题，但请考虑移至springdoc，most recent release 支持 Spring Boot 2.6.0。 Springfox 在这一点上是如此的错误，以至于使用起来很痛苦。由于 Spring WebFlux 支持，我在 2 年前搬到了 springdoc，对此我感到非常高兴。此外，它还支持 Kotlin Coroutines，我不确定 Springfox 是否支持。

如果您决定迁移，springdoc 甚至还有一个migration guide。

【讨论】：

【解决方案2】：

到目前为止，Springfox 3.0.0 仅适用于 Spring 2.6.0-M2，但不适用于以上版本。请参阅公开的 Springfox 问题https://github.com/springfox/springfox/issues/3462。在那里，您还可以找到一些在问题得到解决之前可以使用的解决方法。

例如将此Bean 添加到您的 Swagger 配置中：

@Bean
public static BeanPostProcessor springfoxHandlerProviderBeanPostProcessor() {
    return new BeanPostProcessor() {

        @Override
        public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
            if (bean instanceof WebMvcRequestHandlerProvider || bean instanceof WebFluxRequestHandlerProvider) {
                customizeSpringfoxHandlerMappings(getHandlerMappings(bean));
            }
            return bean;
        }

        private <T extends RequestMappingInfoHandlerMapping> void customizeSpringfoxHandlerMappings(List<T> mappings) {
            List<T> copy = mappings.stream()
                .filter(mapping -> mapping.getPatternParser() == null)
                .collect(Collectors.toList());
            mappings.clear();
            mappings.addAll(copy);
        }

        @SuppressWarnings("unchecked")
        private List<RequestMappingInfoHandlerMapping> getHandlerMappings(Object bean) {
            try {
                Field field = ReflectionUtils.findField(bean.getClass(), "handlerMappings");
                field.setAccessible(true);
                return (List<RequestMappingInfoHandlerMapping>) field.get(bean);
            } catch (IllegalArgumentException | IllegalAccessException e) {
                throw new IllegalStateException(e);
            }
        }
    };
}

编辑：服务器启动，但没有返回 API 信息：

规范中没有定义操作！

真是一团糟。

编辑2：正如@Héctor 所说，spring.mvc.pathmatch.matching-strategy=ANT_PATH_MATCHER 也必须添加到application.properties，然后再次显示操作。但是，我不知道是否可以在任何情况下设置此属性，因为它可能会干扰其他约束。

【讨论】：

我在这个网址中找到，最后的解决方法：将“spring.mvc.pathmatch.matching-strategy=ANT_PATH_MATCHER”添加到你的application.properties。就是这样
@Héctor：感谢您的意见。但是，我需要定义BeanPostProcessor 并添加ANT_PATH_MATCHER。仅添加ANT_PATH_MATCHER 会导致与@Thirumal 所述相同的错误。

【解决方案3】：

迁移步骤：

<dependency>
    <groupId>io.springfox</groupId>
    <artifactId>springfox-boot-starter</artifactId>
    <version>3.0.0</version>
</dependency>

仅维护上述依赖项。
删除早期版本的库包含。专门删除 springfox-swagger2 和 springfox-swagger-ui 包含。
删除@EnableSwagger2 注释
添加 springfox-boot-starter
Springfox 3.x 删除了对 guava 和其他 3rd 方库的依赖（还不是零依赖！依赖于 spring 插件和开放的注释和模型的 api 库），所以如果你使用了 guava 谓词/函数，则需要转换到 java 8个功能接口
如果您正在使用 WebMvc 但尚未使用 @EnableWebMvc 注解，请添加此注解。

来源：doc_link

【讨论】：

对于绝大多数人来说，将 @EnableWebMvc 添加到 Spring Boot 应用程序是错误的做法，因为它会禁用 Spring Boot 的 Spring MVC 自动配置。
使用外部依赖的 SNAPSHOT 版本不是一个好主意。这以可能非常令人惊讶的方式使构建不可重复。

【解决方案4】：

对于 springfox 3.0.0 和 springboot 2.6.1 使用这个配置并添加这个标签 @Configuration @EnableWebMvc

public class SpringFoxConfig {

    @Bean
    public Docket api() {
        return new Docket(DocumentationType.SWAGGER_2)
                .select()
                .apis(RequestHandlerSelectors.withClassAnnotation(RestController.class))
                .paths(PathSelectors.any())
                .build().apiInfo(getApiInfo());
    }
    
    private ApiInfo getApiInfo() {
        return new ApiInfo(
                "Api Usuarios",
                "prueba global logic",
                "1",
                "TERMS OF SERVICE URL",
                new Contact("Gabriel Hernández","URL","gabriel.hernandez.u@gmail.com"),
                "LICENSE",
                "LICENSE URL",
                Collections.emptyList()
        );
    }
    
    @Bean
    public static BeanPostProcessor springfoxHandlerProviderBeanPostProcessor() {
        return new BeanPostProcessor() {

            @Override
            public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
                if (bean instanceof WebMvcRequestHandlerProvider ) {
                    customizeSpringfoxHandlerMappings(getHandlerMappings(bean));
                }
                return bean;
            }

            private <T extends RequestMappingInfoHandlerMapping> void customizeSpringfoxHandlerMappings(List<T> mappings) {
                List<T> copy = mappings.stream()
                    .filter(mapping -> mapping.getPatternParser() == null)
                    .collect(Collectors.toList());
                mappings.clear();
                mappings.addAll(copy);
            }

            @SuppressWarnings("unchecked")
            private List<RequestMappingInfoHandlerMapping> getHandlerMappings(Object bean) {
                try {
                    Field field = ReflectionUtils.findField(bean.getClass(), "handlerMappings");
                    field.setAccessible(true);
                    return (List<RequestMappingInfoHandlerMapping>) field.get(bean);
                } catch (IllegalArgumentException | IllegalAccessException e) {
                    throw new IllegalStateException(e);
                }
            }
        };
    }    
}

【讨论】：