#yyds干货盘点#SpringBoot集成Swagger版本不兼容

新项目当然都要新版本咯！这不集成Swagger就有问题了，不过问题不大【别慌！都是小场面】IDEA新建SpringBoot项目版本是2.7.5，所有的org.springframework.boot版本都是2.7.5，但是我用的Swagger版本还是之前的2.6.1，然后启动的时候报错了

Caused by: 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)
  at org.springframework.context.support.DefaultLifecycleProcessor.access$200(DefaultLifecycleProcessor.java:54)
  at org.springframework.context.support.DefaultLifecycleProcessor$LifecycleGroup.start(DefaultLifecycleProcessor.java:356)
  at 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.SpringApplication.refresh(SpringApplication.java:734)
  at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:408)
  at org.springframework.boot.SpringApplication.run(SpringApplication.java:308)
  at org.springframework.boot.test.context.SpringBootContextLoader.loadContext(SpringBootContextLoader.java:132)
  at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:141)
  at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:90)
  ... 67 common frames omitted
Caused by: java.lang.NullPointerException: 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$3(Orderings.java:89)
  at java.util.Comparator.lambda$comparing$77a9974f$1(Comparator.java:469)
  at java.util.TimSort.countRunAndMakeAscending(TimSort.java:355)
  at java.util.TimSort.sort(TimSort.java:220)
  at java.util.Arrays.sort(Arrays.java:1512)
  at java.util.ArrayList.sort(ArrayList.java:1462)
  at java.util.stream.SortedOps$RefSortingSink.end(SortedOps.java:387)
  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:482)
  at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471)
  at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:708)
  at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
  at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:499)
  at springfox.documentation.spring.web.plugins.WebMvcRequestHandlerProvider.requestHandlers(WebMvcRequestHandlerProvider.java:81)
  at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193)
  at java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1382)
  at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:481)
  at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471)
  at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:708)
  at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
  at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:499)
  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)
  ... 80 common frames omitted

简化一下，大概是这样的

Caused by: org.springframework.context.ApplicationContextException: Failed to start bean 'documentationPluginsBootstrapper'; nested exception is java.lang.NullPointerException
Caused by: java.lang.NullPointerException

想着既然SpringBoot版本高，那Swagger版本也升级就好了，所以果断把Swagger升级到3.0.0【如果不知道Maven依赖版本可以打开​​https://mvnrepository.com​​​搜索，类似这样​​https://mvnrepository.com/artifact/io.springfox/springfox-boot-starter​​】

看一下发现原来配置Swagger需要springfox-swagger2和springfox-swagger-ui，现在只需要springfox-boot-starter。所以整个pom.xml代码是这样的【如果项目需要旧版本就放开旧版本的注释，把新版本注释】

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.7.5</version>
        <!--以下是旧版本 集成swagger -->
        <!--<version>2.1.4.RELEASE</version>-->
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>tool</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>tool</name>
    <description>tool</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <!--集成新版本swagger 只需要springfox-boot-starter-->
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-boot-starter</artifactId>
            <version>3.0.0</version>
        </dependency>

        <!--集成旧版本版本swagger 需要springfox-swagger2和springfox-swagger-ui-->
<!--        <dependency>-->
<!--            <groupId>io.springfox</groupId>-->
<!--            <artifactId>springfox-swagger2</artifactId>-->
<!--            <version>2.6.1</version>-->
<!--        </dependency>-->
<!--        <dependency>-->
<!--            <groupId>io.springfox</groupId>-->
<!--            <artifactId>springfox-swagger-ui</artifactId>-->
<!--            <version>2.6.1</version>-->
<!--        </dependency>-->
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

当然新版本在配置文件【application.properties】还要添加

#集成Swagger高版本启动异常配置，低版本可以不配置
spring.mvc.pathmatch.matching-strategy=ant-path-matcher

送佛送到西，把SwaggerConfig.java文件拿出来

package com.example.tool.config;


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.spi.DocumentationType;
import springfox.documentation.spring.web.plugins.Docket;
import springfox.documentation.swagger2.annotations.EnableSwagger2;


@EnableSwagger2
@Configuration
public class Swagger2Config {

    @Bean
    public Docket createRestApi() {
        return new Docket(DocumentationType.SWAGGER_2)
                .apiInfo(apiInfo())
                .select()
                .apis(RequestHandlerSelectors.basePackage("com.example.tool.controller"))
                .paths(PathSelectors.any())
                .build();
    }

    //构建 api文档的详细信息函数
    private ApiInfo apiInfo() {
        return new ApiInfoBuilder()
                //页面标题
                .title("接口文档")
                //版本号
                .version("1.0")
                //描述
                .description("这是一个比较粗糙的文档，请将就一点点")
                .build();
    }
}

整个项目的结构就是初始化项目结构，信我啦！

最后就是访问Swagger页面啦！首先启动项目，然后打开访问地址，此处访问地址是重点，不同版本访问地址不同！！！

旧版本访问swagger地址是：

http://localhost:8080/swagger-ui.html

​​ 新版本访问swagger地址是：

http://localhost:8080/swagger-ui/index.html

实在不知道访问地址可以打开external libraries看一下，类似这样【我看的这个是新版本的，上面端口是项目默认端口，如果你们有设置端口要改成你们设置端口哦！】

完工，你也赶紧来试试吧！