springboot 配置Knife4j- Swagger3.0

一、导入maven包

    <dependency>
            <groupId>com.github.xiaoymin</groupId>
            <artifactId>knife4j-spring-boot-starter</artifactId>
            <version>3.0.2</version>
    </dependency>

二、配置config-swagger工具

package com.exceltotxt.demo.config;

import com.github.xiaoymin.knife4j.spring.annotations.EnableKnife4j;
import com.github.xiaoymin.knife4j.spring.extension.OpenApiExtensionResolver;
import io.swagger.annotations.ApiOperation;
import org.springframework.beans.factory.annotation.Autowired;
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.service.ApiInfo;
import springfox.documentation.service.Contact;
import springfox.documentation.spi.DocumentationType;
import springfox.documentation.spring.web.plugins.Docket;

/**
 * @ClassName SwaggerConfiguration
 * @Description TODO
 * @Author arthur_Yang
 * @Date 2023年7月18日12:39:32
 * Version 1.0
 **/

@Configuration
@EnableKnife4j
public class SwaggerConfiguration {

    private final OpenApiExtensionResolver openApiExtensionResolver;

    @Autowired
    public SwaggerConfiguration(OpenApiExtensionResolver openApiExtensionResolver) {
        this.openApiExtensionResolver = openApiExtensionResolver;
    }

    @Bean(value = "defaultApi")
    public Docket defaultApi() {
        String groupName = "在线API接口地址";
        Docket docket = new Docket(DocumentationType.SWAGGER_2)
                .host("https://www.baidu.com")
                .apiInfo(apiInfo())
                .pathMapping("/")
                .groupName(groupName)
                .select()
                .apis(RequestHandlerSelectors.withMethodAnnotation(ApiOperation.class))
                .paths(PathSelectors.regex("/.*"))
                .build()
                .extensions(openApiExtensionResolver.buildExtensions(groupName));
        return docket;
    }

    private ApiInfo apiInfo() {
        return new ApiInfoBuilder()
                .title("XXX智能系统")
                .description("XXX系统在线API接口文档！")
                .termsOfServiceUrl("NO terms of service")
                .license("The Apache License, Version 2.0")
                .licenseUrl("http://www.apache.org/licenses/LICENSE-2.0.html")
                .contact(contactInfo())
                .version("1.0")
                .build();
    }

    private Contact contactInfo() {
        Contact contact = new Contact("XX公司", "www.baidu.com", "XX@email.com");
        return contact;
    }
}

三、配置yml文件

knife4j:
  enable: true
  setting:
    enableOpenApi: false
    enableFooter: false
    enableFooterCustom: true
    footerCustomContent: Apache License 2.0 | Copyright  @2020-2025 | [XXXX公司](http://www.baidu.com)

四、启动项目访问http://localhost:8080/doc.html

五、注意，启动的时候会报如下错误

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) ~[?:?]
	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 com.iscas.biz.BizApp.main(BizApp.java:69) ~[classes/:?]
Caused by: java.lang.NullPointerException
	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$1(Comparator.java:469) ~[?:?]
	at java.util.TimSort.countRunAndMakeAscending(TimSort.java:355) ~[?:?]
	at java.util.TimSort.sort(TimSort.java:234) ~[?:?]
	at java.util.Arrays.sort(Arrays.java:1515) ~[?:?]
	at java.util.ArrayList.sort(ArrayList.java:1750) ~[?:?]
	at java.util.stream.SortedOps$RefSortingSink.end(SortedOps.java:392) ~[?:?]
	at java.util.stream.Sink$ChainedReference.end(Sink.java:258) ~[?:?]
	at java.util.stream.Sink$ChainedReference.end(Sink.java:258) ~[?:?]
	at java.util.stream.Sink$ChainedReference.end(Sink.java:258) ~[?:?]
	at java.util.stream.Sink$ChainedReference.end(Sink.java:258) ~[?:?]
	at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:485) ~[?:?]
	at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474) ~[?:?]
	at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:913) ~[?:?]
	at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) ~[?:?]
	at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:578) ~[?:?]
	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$1.accept(ReferencePipeline.java:195) ~[?:?]
	at java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1655) ~[?:?]
	at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484) ~[?:?]
	at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474) ~[?:?]
	at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:913) ~[?:?]
	at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) ~[?:?]
	at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:578) ~[?:?]
	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-5.3.13.jar:5.3.13]
	... 12 more

六、解决方案可以参考https://blog.csdn.net/xueyushenzhou/article/details/127091559

另外一种解决方案：降低springboot 版本为2.6.0或2.6以下

  <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.6.0</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>