解决springboot接入springfox-swagger2遇到的一些问题
作者：程序员涵堉
springboot接入springfox-swagger2的问题
springfox-swagger2目前最新的版本是3.0，不过已经是2020年的，对springboot新版的适配已经不是多么友好了。
应该是在springboot2.6以上的版本集成springfox-swagger2的时候会有各种问题存在。
一下是一个springboot2.7.10集成swagger的例子：
1、引入springfox-swagger的jar文件
<!--swagger-->
<dependency>
<groupId>io.springfox</groupId>
<artifactId>springfox-boot-starter</artifactId>
<version>3.0.0</version>
</dependency>2、配置swagger的配置文件(SwaggerConfig.java)
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import springfox.documentation.builders.ApiInfoBuilder;
import springfox.documentation.builders.PathSelectors;
import springfox.documentation.builders.RequestHandlerSelectors;
import springfox.documentation.oas.annotations.EnableOpenApi;
import springfox.documentation.service.ApiInfo;
import springfox.documentation.service.Contact;
import springfox.documentation.spi.DocumentationType;
import springfox.documentation.spring.web.plugins.Docket;
/**
* @ClassName swaggerConfig
* @Description: TODO
* @Author:1276046082@qq.com
*/
@Configuration
@EnableOpenApi
public class SwaggerConfig {
/**
* 创建API应用
* apiInfo() 增加API相关信息
* 通过select()函数返回一个ApiSelectorBuilder实例,用来控制哪些接口暴露给Swagger来展现，
* 本例采用指定扫描的包路径来定义指定要建立API的目录。
*
* @return
*/
@Bean
public Docket restApi() {
return new Docket(DocumentationType.SWAGGER_2)
.groupName("标准接口")
.apiInfo(apiInfo("Spring Boot中使用Swagger2构建RESTful APIs", "1.0"))
.useDefaultResponseMessages(true)
.forCodeGeneration(false)
.select()
.apis(RequestHandlerSelectors.basePackage("com.ithanyu.controller"))
.paths(PathSelectors.any())
.build();
}
/**
* 创建该API的基本信息（这些基本信息会展现在文档页面中）
* 访问地址：http://ip:port/swagger-ui.html
*
* @return
*/
private ApiInfo apiInfo(String title, String version) {
return new ApiInfoBuilder()
.title(title)
.description("更多请关注: https://blog.csdn.net/zy1276046082")
.termsOfServiceUrl("https://blog.csdn.net/zy1276046082")
.contact(new Contact("zyhanyu", "https://blog.csdn.net/zy1276046082", "1276046082@qq.com"))
.version(version)
.build();
}
}如果使用低版本的springboot比如2.6以下的，基本上都可以成功的。
但是使用2.6以上版本，这个时候可能会报启动失败
Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2023-10-24 23:26:19.235 ERROR 28432 --- [ main] o.s.boot.SpringApplication : Application run failedorg.springframework.context.ApplicationContextException: Failed to start bean 'documentationPluginsBootstrapper'; nested exception is java.lang.NullPointerException
at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:182) ~[spring-context-5.3.30.jar:5.3.30]
at org.springframework.context.support.DefaultLifecycleProcessor.access$200(DefaultLifecycleProcessor.java:54) ~[spring-context-5.3.30.jar:5.3.30]
at org.springframework.context.support.DefaultLifecycleProcessor$LifecycleGroup.start(DefaultLifecycleProcessor.java:357) ~[spring-context-5.3.30.jar:5.3.30]
at java.lang.Iterable.forEach(Iterable.java:75) ~[na:1.8.0_201]
at org.springframework.context.support.DefaultLifecycleProcessor.startBeans(DefaultLifecycleProcessor.java:156) ~[spring-context-5.3.30.jar:5.3.30]
at org.springframework.context.support.DefaultLifecycleProcessor.onRefresh(DefaultLifecycleProcessor.java:124) ~[spring-context-5.3.30.jar:5.3.30]
at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:938) ~[spring-context-5.3.30.jar:5.3.30]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:586) ~[spring-context-5.3.30.jar:5.3.30]
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:147) ~[spring-boot-2.7.17.jar:2.7.17]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:732) [spring-boot-2.7.17.jar:2.7.17]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:409) [spring-boot-2.7.17.jar:2.7.17]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:308) [spring-boot-2.7.17.jar:2.7.17]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1300) [spring-boot-2.7.17.jar:2.7.17]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1289) [spring-boot-2.7.17.jar:2.7.17]
at com.ithanyu.Application.main(Application.java:17) [classes/:na]
Caused by: java.lang.NullPointerException: null
at springfox.documentation.spring.web.WebMvcPatternsRequestConditionWrapper.getPatterns(WebMvcPatternsRequestConditionWrapper.java:56) ~[springfox-spring-webmvc-3.0.0.jar:3.0.0]
at springfox.documentation.RequestHandler.sortedPaths(RequestHandler.java:113) ~[springfox-core-3.0.0.jar:3.0.0]
at springfox.documentation.spi.service.contexts.Orderings.lambda$byPatternsCondition$3(Orderings.java:89) ~[springfox-spi-3.0.0.jar:3.0.0]
at java.util.Comparator.lambda$comparing$77a9974f$1(Comparator.java:469) ~[na:1.8.0_201]
at java.util.TimSort.countRunAndMakeAscending(TimSort.java:355) ~[na:1.8.0_201]
at java.util.TimSort.sort(TimSort.java:220) ~[na:1.8.0_201]
at java.util.Arrays.sort(Arrays.java:1512) ~[na:1.8.0_201]
at java.util.ArrayList.sort(ArrayList.java:1462) ~[na:1.8.0_201]
at java.util.stream.SortedOps$RefSortingSink.end(SortedOps.java:387) ~[na:1.8.0_201]
at java.util.stream.Sink$ChainedReference.end(Sink.java:258) ~[na:1.8.0_201]
at java.util.stream.Sink$ChainedReference.end(Sink.java:258) ~[na:1.8.0_201]
at java.util.stream.Sink$ChainedReference.end(Sink.java:258) ~[na:1.8.0_201]
at java.util.stream.Sink$ChainedReference.end(Sink.java:258) ~[na:1.8.0_201]
at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:482) ~[na:1.8.0_201]
at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471) ~[na:1.8.0_201]
at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:708) ~[na:1.8.0_201]
at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) ~[na:1.8.0_201]
at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:499) ~[na:1.8.0_201]
at springfox.documentation.spring.web.plugins.WebMvcRequestHandlerProvider.requestHandlers(WebMvcRequestHandlerProvider.java:81) ~[springfox-spring-webmvc-3.0.0.jar:3.0.0]
at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193) ~[na:1.8.0_201]
at java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1382) ~[na:1.8.0_201]
at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:481) ~[na:1.8.0_201]
at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471) ~[na:1.8.0_201]
at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:708) ~[na:1.8.0_201]
at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) ~[na:1.8.0_201]
at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:499) ~[na:1.8.0_201]
at springfox.documentation.spring.web.plugins.AbstractDocumentationPluginsBootstrapper.withDefaults(AbstractDocumentationPluginsBootstrapper.java:107) ~[springfox-spring-web-3.0.0.jar:3.0.0]
at springfox.documentation.spring.web.plugins.AbstractDocumentationPluginsBootstrapper.buildContext(AbstractDocumentationPluginsBootstrapper.java:91) ~[springfox-spring-web-3.0.0.jar:3.0.0]
at springfox.documentation.spring.web.plugins.AbstractDocumentationPluginsBootstrapper.bootstrapDocumentationPlugins(AbstractDocumentationPluginsBootstrapper.java:82) ~[springfox-spring-web-3.0.0.jar:3.0.0]
at springfox.documentation.spring.web.plugins.DocumentationPluginsBootstrapper.start(DocumentationPluginsBootstrapper.java:100) ~[springfox-spring-web-3.0.0.jar:3.0.0]
at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:179) ~[spring-context-5.3.30.jar:5.3.30]
... 14 common frames omitted
Process finished with exit code 1
这个问题经查询跟springboot的bean初始化有关系，后续的版本更改了相关的东西，具体是什么没有
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.lang.NonNull;
import org.springframework.util.ReflectionUtils;
import org.springframework.web.servlet.mvc.method.RequestMappingInfoHandlerMapping;
import springfox.documentation.spring.web.plugins.WebFluxRequestHandlerProvider;
import springfox.documentation.spring.web.plugins.WebMvcRequestHandlerProvider;
import java.lang.reflect.Field;
import java.util.List;
import java.util.stream.Collectors;
/**
* swagger config
*
* @author zxl
* @date 2023-05-16
*/
@Configuration
public class SwaggerConfig {
@Bean
public BeanPostProcessor springfoxHandlerProviderBeanPostProcessor() {
return new BeanPostProcessor() {
@Override
public Object postProcessAfterInitialization(@NonNull Object bean, @NonNull 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");
assert field != null;
field.setAccessible(true);
return (List<RequestMappingInfoHandlerMapping>) field.get(bean);
} catch (IllegalArgumentException | IllegalAccessException e) {
throw new IllegalStateException(e);
}
}
};
}
}细究，反正参照stackoverflow中的修改方法，加入一下配置类就可以避免错误
加入后启动正常，但是访问swagger的/v2/api-docs接口，发现没有获得数据，接口内容是空的。
这是通过搜索得到有几种解决方案
- 1、ShortVideoSwagger2的配置类需要集成WebMvcConfigurationSupport
- 2、ShortVideoSwagger2的配置类增加@EnableWebMvc注解
- 3、springboot的配置增加增加一下配置
spring:
mvc:
pathmatch:
matching-strategy: ANT_PATH_MATCHER通过试验得知，这三种接口都可以解决，但是前两种是有副总用的
@EnableWebMvc建议慎用，最后在非springboot项目中使用
前两种解决方案会破坏springboot对springwebmvc的自动装配，导致自定义的一些convertor或者ObjectMapper失效。
目前我的项目中是自定义的ObjectMapper失效。
所以最后使用第三种方式，后期的springboot版本的matching-strategy默认的改为了PATH_PATTERN_PARSER，把它改为ANT_PATH_MATCHER就可以了。
总结
以上为个人经验，希望能给大家一个参考，也希望大家多多支持脚本之家。