背景

springboot 集成 swagger3.0 启动报错

• springboot 版本 2.7.2

<parent>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-parent</artifactId>
	<version>2.7.2</version>
	<relativePath/> <!-- lookup parent from repository -->
</parent>

---

• swagger 版本 3.0.0

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

• 错误信息

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-5.3.22.jar:5.3.22]
	at org.springframework.context.support.DefaultLifecycleProcessor.access$200(DefaultLifecycleProcessor.java:54) ~[spring-context-5.3.22.jar:5.3.22]
	at org.springframework.context.support.DefaultLifecycleProcessor$LifecycleGroup.start(DefaultLifecycleProcessor.java:356) ~[spring-context-5.3.22.jar:5.3.22]
	at java.base/java.lang.Iterable.forEach(Iterable.java:75) ~[na:na]
	at org.springframework.context.support.DefaultLifecycleProcessor.startBeans(DefaultLifecycleProcessor.java:155) ~[spring-context-5.3.22.jar:5.3.22]
	at org.springframework.context.support.DefaultLifecycleProcessor.onRefresh(DefaultLifecycleProcessor.java:123) ~[spring-context-5.3.22.jar:5.3.22]
	at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:935) ~[spring-context-5.3.22.jar:5.3.22]
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:586) ~[spring-context-5.3.22.jar:5.3.22]
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:147) ~[spring-boot-2.7.2.jar:2.7.2]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:734) ~[spring-boot-2.7.2.jar:2.7.2]
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:408) ~[spring-boot-2.7.2.jar:2.7.2]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:308) ~[spring-boot-2.7.2.jar:2.7.2]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1306) ~[spring-boot-2.7.2.jar:2.7.2]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1295) ~[spring-boot-2.7.2.jar:2.7.2]
	at com.genew.ims.GenewImsApiApplication.main(GenewImsApiApplication.java:12) ~[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$3(Orderings.java:89) ~[springfox-spi-3.0.0.jar:3.0.0]
	at java.base/java.util.Comparator.lambda$comparing$77a9974f$1(Comparator.java:469) ~[na:na]
	at java.base/java.util.TimSort.countRunAndMakeAscending(TimSort.java:355) ~[na:na]
	at java.base/java.util.TimSort.sort(TimSort.java:220) ~[na:na]
	at java.base/java.util.Arrays.sort(Arrays.java:1515) ~[na:na]
	at java.base/java.util.ArrayList.sort(ArrayList.java:1750) ~[na:na]
	at java.base/java.util.stream.SortedOps$RefSortingSink.end(SortedOps.java:392) ~[na:na]
	at java.base/java.util.stream.Sink$ChainedReference.end(Sink.java:258) ~[na:na]
	at java.base/java.util.stream.Sink$ChainedReference.end(Sink.java:258) ~[na:na]
	at java.base/java.util.stream.Sink$ChainedReference.end(Sink.java:258) ~[na:na]
	at java.base/java.util.stream.Sink$ChainedReference.end(Sink.java:258) ~[na:na]
	at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:485) ~[na:na]
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474) ~[na:na]
	at java.base/java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:913) ~[na:na]
	at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) ~[na:na]
	at java.base/java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:578) ~[na:na]
	at springfox.documentation.spring.web.plugins.WebMvcRequestHandlerProvider.requestHandlers(WebMvcRequestHandlerProvider.java:81) ~[springfox-spring-webmvc-3.0.0.jar:3.0.0]
	at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:195) ~[na:na]
	at java.base/java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1655) ~[na:na]
	at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484) ~[na:na]
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474) ~[na:na]
	at java.base/java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:913) ~[na:na]
	at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) ~[na:na]
	at java.base/java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:578) ~[na:na]
	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:178) ~[spring-context-5.3.22.jar:5.3.22]
	... 14 common frames omitted

解决方式

方式一

• 配置 spring.mvc.pathmatch.matching-strategy=ant_path_matcher

spring:
  profiles:
    active: dev
  # springboot 2.6 及以上 集成swagger 3.0 启动报错问题（新PathPatternParser导致）
  mvc:
    pathmatch:
      matching-strategy: ant_path_matcher

方式二

• 在swagger配置类中添加@EnableWebMvc 注解

package com.example.demo.config;

import io.swagger.annotations.Api;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.env.Environment;
import org.springframework.core.env.Profiles;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import springfox.documentation.builders.ApiInfoBuilder;
import springfox.documentation.builders.PathSelectors;
import springfox.documentation.builders.RequestHandlerSelectors;
import springfox.documentation.service.ApiInfo;
import springfox.documentation.service.Contact;
import springfox.documentation.spi.DocumentationType;
import springfox.documentation.spring.web.plugins.Docket;

/**
 * swagger3 简单配置
 */
@Configuration
@EnableWebMvc
public class SwaggerConfig {

    @Bean
    public Docket createRestApi(Environment environment) {
        //设置要显示的Swagger环境，监听dev，test环境
        Profiles profiles = Profiles.of("dev", "test");
        //通过environment.acceptsProfiles(环境监听变量)判断是否处在自己设定的环境当中
        boolean enable = environment.acceptsProfiles(profiles);

        return new Docket(DocumentationType.OAS_30)
                .enable(enable)
                //.pathMapping("/")
                .select()
                .apis(RequestHandlerSelectors.basePackage("com.example.demo"))
                // controller类上标注@Api注解扫描，没标注的不会显示
                .apis(RequestHandlerSelectors.withClassAnnotation(Api.class))
                .paths(PathSelectors.any())
                .build()
                .apiInfo(apiInfo);
    }

    ApiInfo apiInfo = new ApiInfoBuilder()
            .title("Test api doc")
            .description("这个是描述")
            .version("1.0")
            .contact(new Contact("zhangsan", "", "zhangsan@qq.com"))
            //.license("The apache Licnese")
            //.licenseUrl("")
            .build();

}

其他

swagger3.0 版本集成过程中 发现.apis(RequestHandlerSelectors.basePackage("com.example.*.controller")) 通配符方式扫描包， 该方式不生效（母鸡为甚米）

• 处理方式一

扫描到所有controller的上一层；所以开发过程中，包层级和命名需注意

• 处理方式二
• 写法一

.apis(Predicates.or(          RequestHandlerSelectors.basePackage("com.example.demo.controller"),
 RequestHandlerSelectors.basePackage("com.example.demo2.controller")))

固定路径，配置多个包路径

• 写法二

 com.google.common.base.Predicate<RequestHandler> selector1 = RequestHandlerSelectors.basePackage("com.example.demo.controller");
com.google.common.base.Predicate<RequestHandler> selector2 = RequestHandlerSelectors.basePackage("com.example.demo2.controller");

 .apis(Predicates.or(selector1,selector2))