Spring Boot2.x集成Swagger2 2.9.x解决方案

语言：java

环境：Spring Boot 2.0.3RELEASE+Swagger2 2.9.2+Swagger ui 2.9.2

最近想用最新的swagger2为服务端生成api文档，在此记录一下集成过程遇到的坑：

问题1：swagger ui页面不显示系统接口，然而网上找一圈全是swagger2 2.7以下的版本，还有人提到只要版本高于2.7的都会遇到这个问题。

解决方案：

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;
import springfox.documentation.swagger2.annotations.EnableSwagger2;

/**
 * Swagger2配置类
 * @author gxh
 *
 */
@Configuration
@EnableSwagger2
public class Swagger2 {

	
    @Bean
    public Docket createRestApi() {
        return new Docket(DocumentationType.SWAGGER_2)
                .apiInfo(apiInfo())
                .select()
                .apis(RequestHandlerSelectors.basePackage("com.**.**."))/项目web层所在路径
                .paths(PathSelectors.any())
                .build();
    }

    private ApiInfo apiInfo() {
        return new ApiInfoBuilder()
                .title("API OF PO")
                .description("接口说明文档")
                .contact(new Contact("gxh", null, "[email protected]"))
                .version("1.0-Beta")
                .build();
    }

}

问题2：集成过程报错：

org.springframework.context.ApplicationContextException: Failed to start bean 'documentationPluginsBootstrapper'; nested exception is com.google.common.util.concurrent.ExecutionError: java.lang.NoSuchMethodError: com.google.common.collect.FluentIterable.concat(Ljava/lang/Iterable;Ljava/lang/Iterable;)Lcom/google/common/collect/FluentIterable;
    at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:184) ~[spring-context-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.context.support.DefaultLifecycleProcessor.access$200(DefaultLifecycleProcessor.java:52) ~[spring-context-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.context.support.DefaultLifecycleProcessor$LifecycleGroup.start(DefaultLifecycleProcessor.java:356) ~[spring-context-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.context.support.DefaultLifecycleProcessor.startBeans(DefaultLifecycleProcessor.java:157) ~[spring-context-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.context.support.DefaultLifecycleProcessor.onRefresh(DefaultLifecycleProcessor.java:121) ~[spring-context-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:885) ~[spring-context-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.finishRefresh(ServletWebServerApplicationContext.java:161) ~[spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:553) ~[spring-context-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:140) ~[spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:759) [spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:395) [spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:327) [spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1255) [spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1243) [spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    at com.ins.sys.SysApplication.main(SysApplication.java:12) [classes/:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_171]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_171]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_171]
    at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_171]
    at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) [spring-boot-devtools-2.0.3.RELEASE.jar:2.0.3.RELEASE]
Caused by: com.google.common.util.concurrent.ExecutionError: java.lang.NoSuchMethodError: com.google.common.collect.FluentIterable.concat(Ljava/lang/Iterable;Ljava/lang/Iterable;)Lcom/google/common/collect/FluentIterable;
    at com.google.common.cache.LocalCache$Segment.get(LocalCache.java:2201) ~[guava-18.0.jar:na]
    at com.google.common.cache.LocalCache.get(LocalCache.java:3937) ~[guava-18.0.jar:na]
    at com.google.common.cache.LocalCache.getOrLoad(LocalCache.java:3941) ~[guava-18.0.jar:na]
    at com.google.common.cache.LocalCache$LocalLoadingCache.get(LocalCache.java:4824) ~[guava-18.0.jar:na]
    at springfox.documentation.schema.CachingModelDependencyProvider.dependentModels(CachingModelDependencyProvider.java:58) ~[springfox-schema-2.9.2.jar:null]
    at springfox.documentation.schema.DefaultModelProvider.dependencies(DefaultModelProvider.java:128) ~[springfox-schema-2.9.2.jar:null]
    at springfox.documentation.schema.CachingModelProvider.dependencies(CachingModelProvider.java:68) ~[springfox-schema-2.9.2.jar:null]
    at springfox.documentation.spring.web.scanners.ApiModelReader.populateDependencies(ApiModelReader.java:136) ~[springfox-spring-web-2.9.2.jar:null]
    at springfox.documentation.spring.web.scanners.ApiModelReader.read(ApiModelReader.java:78) ~[springfox-spring-web-2.9.2.jar:null]
    at springfox.documentation.spring.web.scanners.ApiListingScanner.scan(ApiListingScanner.java:133) ~[springfox-spring-web-2.9.2.jar:null]
    at springfox.documentation.spring.web.scanners.ApiDocumentationScanner.scan(ApiDocumentationScanner.java:71) ~[springfox-spring-web-2.9.2.jar:null]
    at springfox.documentation.spring.web.plugins.DocumentationPluginsBootstrapper.scanDocumentation(DocumentationPluginsBootstrapper.java:101) ~[springfox-spring-web-2.9.2.jar:null]
    at springfox.documentation.spring.web.plugins.DocumentationPluginsBootstrapper.start(DocumentationPluginsBootstrapper.java:167) ~[springfox-spring-web-2.9.2.jar:null]
    at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:181) ~[spring-context-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    ... 19 common frames omitted
Caused by: java.lang.NoSuchMethodError: com.google.common.collect.FluentIterable.concat(Ljava/lang/Iterable;Ljava/lang/Iterable;)Lcom/google/common/collect/FluentIterable;
    at springfox.documentation.schema.DefaultModelDependencyProvider.dependentModels(DefaultModelDependencyProvider.java:79) ~[springfox-schema-2.9.2.jar:null]
    at springfox.documentation.schema.CachingModelDependencyProvider$1.load(CachingModelDependencyProvider.java:50) ~[springfox-schema-2.9.2.jar:null]
    at springfox.documentation.schema.CachingModelDependencyProvider$1.load(CachingModelDependencyProvider.java:48) ~[springfox-schema-2.9.2.jar:null]
    at com.google.common.cache.LocalCache$LoadingValueReference.loadFuture(LocalCache.java:3527) ~[guava-18.0.jar:na]
    at com.google.common.cache.LocalCache$Segment.loadSync(LocalCache.java:2319) ~[guava-18.0.jar:na]
    at com.google.common.cache.LocalCache$Segment.lockedGetOrLoad(LocalCache.java:2282) ~[guava-18.0.jar:na]
    at com.google.common.cache.LocalCache$Segment.get(LocalCache.java:2197) ~[guava-18.0.jar:na]
    ... 32 common frames omitted

解决方案：由于guava的兼容性导致的问题，引入

<dependency>
    <groupId>com.google.guava</groupId>
    <artifactId>guava</artifactId>
    <version>20.0</version>
</dependency>

即可。

问题完美解决：