OpenApi Not Working with Spring Boot Gradle Project

Question

I am trying to add OpenApi to my Spring Boot Gradle project. I've added the OpenAPI plugin to my build.gradle file, but when I start my app, none of the URLs that are supposed to make documentation seem to get generated.

build.gradle

plugins {
    id 'java'
    id 'org.springframework.boot' version '3.0.1-SNAPSHOT'
    id 'io.spring.dependency-management' version '1.1.0'
    id "org.springdoc.openapi-gradle-plugin" version "1.6.0"
}

group = 'com.sampleproject'
sourceCompatibility = '17'

repositories {
    mavenCentral()
    maven { url 'https://repo.spring.io/milestone' }
    maven { url 'https://repo.spring.io/snapshot' }
}

dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-web'
    testImplementation 'org.springframework.boot:spring-boot-starter-test'
}

tasks.named('test') {
    useJUnitPlatform()
}

application.properties

server.servlet.context-path=/sample-service
springdoc.api-docs.path=/api-docs
springdoc.swagger-ui.path=/swagger-ui-custom.html

I have tried building and running my project with:

• ./gradlew clean build followed by java -jar build/libs/name-of-jar-file.jar
• ./gradlew clean generateOpenApiDocs

Links that I've been using:

• https://springdoc.org/v2/#gradle-plugin
• https://github.com/springdoc/springdoc-openapi-gradle-plugin

Both links say to add the plugin, which I did. When my app is running, I try going to http://localhost:8080/sample-service/api-docs and http://localhost:8080/sample-service/swagger-ui-custom.html, and both give me the standard spring white label error page.

I have two controller classes in my application, and all endpoints work fine when my app is running.

What am I missing or doing wrong in order to get OpenAPI to work with my Spring Boot Gradle application?

Answer 1

In order to enable swagger UI, you will need to add the plugin of

implementation group: 'org.springdoc', name: 'springdoc-openapi-ui', version: '1.6.14'

Adding this to build.gradle dependencies will solve your problem. I hope this helps.