Generating API Documentation using Swagger

Swagger is an open-source software framework that helps developers design, build, document, and consume RESTful web services. With Swagger, you can easily generate interactive API documentation for your Spring Boot applications. In this article, we will explore the steps to generate API documentation using Swagger in a Spring Boot project.

Prerequisites

Before we start, make sure you have the following prerequisites installed:

JDK 8 or above
Maven or Gradle
Spring Boot

Step 1: Add Swagger Dependencies

To begin, we need to add Swagger dependencies to our project. Open your pom.xml file (if using Maven) or build.gradle file (if using Gradle) and include the following dependencies:

<dependencies>
    <!-- Swagger -->
    <dependency>
        <groupId>io.springfox</groupId>
        <artifactId>springfox-boot-starter</artifactId>
        <version>3.0.0</version>
    </dependency>
</dependencies>

Step 2: Configure Swagger

Next, we need to configure Swagger in our Spring Boot application. Create a new Java class named SwaggerConfig and annotate it with @Configuration and @EnableSwagger2 annotations. Here's an example configuration:

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;

@Configuration
@EnableSwagger2
public class SwaggerConfig {

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

    private ApiInfo apiInfo() {
        return new ApiInfoBuilder()
                .title("My REST API")
                .description("API documentation for my Spring Boot application")
                .version("1.0.0")
                .build();
    }
}

Make sure to update the basePackage value in RequestHandlerSelectors.basePackage() method with the package of your REST controllers.

Step 3: Run the Application

With the Swagger configuration in place, you can now run your Spring Boot application. Open your favorite web browser and navigate to http://localhost:8080/swagger-ui/index.html. You should see the Swagger UI interface showing the available API endpoints.

Step 4: Explore API Documentation

Swagger UI provides an interactive interface to explore and test your APIs. You can view detailed information about each endpoint, including the request and response payloads, HTTP methods, and response codes. You can also test the API endpoints directly from the Swagger UI interface.

Conclusion

Generating API documentation using Swagger in a Spring Boot application is straightforward and can greatly simplify the process of documenting and testing your RESTful web services. With Swagger, you can provide an interactive and user-friendly API documentation for your consumers.