通过Knife4j在gateway中对swagger文档进行聚合

Knife4j 集成方案

方案选择

knife4j-micro-spring-boot-starter 和 knife4j-spring-boot-starter
采用聚合方案，选择使用这两个依赖包。
Knife4jAggregation 聚合方案
由于官方文档明确指出其无法与 Spring Cloud Gateway 混合使用，因此放弃该方案。
参考文档：Knife4jAggregation 介绍
knife4j-gateway-spring-boot-starter
由于当前 Spring Cloud 版本较低，存在兼容性问题，因此放弃该方案。
参考文档：Knife4j Gateway 实战文档

使用的依赖包

knife4j-micro-spring-boot-starter
knife4j-spring-boot-starter
版本均为 3.0.3。两者的主要区别在于 knife4j-spring-boot-starter 额外引入了 knife4j-spring-ui（具体可查看依赖关系）。

实现目标

业务模块
引入 knife4j-micro-spring-boot-starter 以生成 Swagger JSON 文档。
Gateway 模块
引入 knife4j-spring-boot-starter 以聚合文档。
Gateway 页面展示
需自行实现 swagger-resource 端点，确保页面正常显示。

代码实现

业务模块

引入依赖

<dependency><groupId>com.github.xiaoymin</groupId><artifactId>knife4j-micro-spring-boot-starter</artifactId><version>3.0.3</version>
</dependency>

代码说明

默认情况下，无需额外配置即可使用。若需开启增强模式，可参考后续章节。

Gateway 模块

引入依赖

<dependency><groupId>com.github.xiaoymin</groupId><artifactId>knife4j-spring-boot-starter</artifactId><version>3.0.3</version>
</dependency>

核心代码

实现以下三个类：

SwaggerHandler
处理 Swagger 资源请求。

package com.hatzi.gateway.swagger;import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import reactor.core.publisher.Mono;
import springfox.documentation.swagger.web.*;import java.util.Optional;@RestController
public class SwaggerHandler {private final SwaggerResourcesProvider swaggerResources;@Autowired(required = false)private SecurityConfiguration securityConfiguration;@Autowired(required = false)private UiConfiguration uiConfiguration;@Autowiredpublic SwaggerHandler(SwaggerResourcesProvider swaggerResources) {this.swaggerResources = swaggerResources;}@GetMapping("/swagger-resources/configuration/security")public Mono<ResponseEntity<SecurityConfiguration>> securityConfiguration() {return Mono.just(new ResponseEntity<>(Optional.ofNullable(securityConfiguration).orElse(SecurityConfigurationBuilder.builder().build()), HttpStatus.OK));}@GetMapping("/swagger-resources/configuration/ui")public Mono<ResponseEntity<UiConfiguration>> uiConfiguration() {return Mono.just(new ResponseEntity<>(Optional.ofNullable(uiConfiguration).orElse(UiConfigurationBuilder.builder().build()), HttpStatus.OK));}@GetMapping("/swagger-resources")public Mono<ResponseEntity> swaggerResources() {return Mono.just((new ResponseEntity<>(swaggerResources.get(), HttpStatus.OK)));}
}

SwaggerHeaderFilter
拦截器，用于处理请求头。

package com.hatzi.gateway.swagger;import org.apache.commons.lang3.StringUtils;
import org.springframework.cloud.gateway.filter.GatewayFilter;
import org.springframework.cloud.gateway.filter.factory.AbstractGatewayFilterFactory;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.stereotype.Component;
import org.springframework.web.server.ServerWebExchange;@Component
public class SwaggerHeaderFilter extends AbstractGatewayFilterFactory {private static final String HEADER_NAME = "X-Forwarded-Prefix";private static final String URI = "/v2/api-docs";@Overridepublic GatewayFilter apply(Object config) {return (exchange, chain) -> {ServerHttpRequest request = exchange.getRequest();String path = request.getURI().getPath();if (!StringUtils.endsWithIgnoreCase(path, URI)) {return chain.filter(exchange);}String basePath = path.substring(0, path.lastIndexOf(URI));ServerHttpRequest newRequest = request.mutate().header(HEADER_NAME, basePath).build();ServerWebExchange newExchange = exchange.mutate().request(newRequest).build();return chain.filter(newExchange);};}
}

SwaggerResourceConfig
配置 Swagger 资源。

package com.hatzi.gateway.swagger;import com.hatzi.core.constant.SwaggerConstant;
import lombok.AllArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.cloud.gateway.config.GatewayProperties;
import org.springframework.cloud.gateway.route.RouteLocator;
import org.springframework.cloud.gateway.support.NameUtils;
import org.springframework.context.annotation.Primary;
import org.springframework.stereotype.Component;
import springfox.documentation.swagger.web.SwaggerResource;
import springfox.documentation.swagger.web.SwaggerResourcesProvider;import java.util.ArrayList;
import java.util.List;@Slf4j
@Component
@Primary
@AllArgsConstructor
public class SwaggerResourceConfig implements SwaggerResourcesProvider {private final RouteLocator routeLocator;private final GatewayProperties gatewayProperties;@Overridepublic List<SwaggerResource> get() {List<SwaggerResource> resources = new ArrayList<>();List<String> routes = new ArrayList<>();routeLocator.getRoutes().subscribe(route -> routes.add(route.getId()));gatewayProperties.getRoutes().stream().filter(routeDefinition -> routes.contains(routeDefinition.getId())).forEach(route -> {route.getPredicates().stream().filter(predicateDefinition -> "Path".equalsIgnoreCase(predicateDefinition.getName())).forEach(predicateDefinition -> {String genKey = predicateDefinition.getArgs().get(NameUtils.GENERATED_NAME_PREFIX + "0");String location = genKey.replace("**", "v2/api-docs");resources.add(swaggerResource(route.getId(), location));});});return resources;}private SwaggerResource swaggerResource(String name, String location) {SwaggerResource swaggerResource = new SwaggerResource();swaggerResource.setName(name);swaggerResource.setLocation(location);swaggerResource.setSwaggerVersion("1.0.0");return swaggerResource;}
}

验证步骤

启动 Gateway 和业务模块
访问业务模块
Swagger JSON 文档正常生成。
访问 Gateway
Gateway 页面正常显示。

增强模式配置

若需使用增强模式（如文档访问密码、标题修改等），需在业务模块中配置增强模式。以下为示例代码：

package com.hatzi.swagger.config;import com.github.xiaoymin.knife4j.spring.annotations.EnableKnife4j;
import com.hatzi.swagger.config.properties.SwaggerProperties;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Import;
import org.springframework.web.bind.annotation.RestController;
import springfox.bean.validators.configuration.BeanValidatorPluginsConfiguration;
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;@Configuration
@EnableSwagger2
@EnableKnife4j
@Import(BeanValidatorPluginsConfiguration.class)
public class SwaggerConfiguration {@Beanpublic Docket defaultApi() {Contact contact = new Contact("作者", "联系url", "邮箱");return new Docket(DocumentationType.SWAGGER_2).apiInfo(apiInfo("接口文档", "接口文档", contact)).select().apis(RequestHandlerSelectors.withClassAnnotation(RestController.class)).paths(PathSelectors.any()).build();}private ApiInfo apiInfo(String title, String description, Contact contact) {return new ApiInfoBuilder().title(title).description(description).contact(contact).build();}
}

常见问题

为什么某些博客提到必须重写 addResourceHandlers 才能使 doc.html 正常访问？
这是因为在 Spring Boot 中，若配置 spring.mvc.add-mappings 为 false，所有映射关系将失效，此时必须重写 addResourceHandlers 方法。
配置说明