Introduction

Creating well-documented APIs is crucial for modern software development. Spring Boot, combined with Swagger, makes it easy to document and test your RESTful APIs. In this guide, we'll explore how to generate API documentation using Swagger in Spring Boot, complete with sample code and detailed explanations.

Prerequisites

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

• A Spring Boot project with RESTful APIs (if you don't have one, follow the "Creating a Simple REST API with Spring Boot" guide)
• An Integrated Development Environment (IDE) like Spring Tool Suite, IntelliJ IDEA, or Visual Studio Code

Adding Swagger to Your Project

To enable Swagger in your Spring Boot project, you need to add the necessary dependencies. Add the following dependencies to your pom.xml:

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

Configuring Swagger

You need to configure Swagger to document your APIs properly. Create a configuration class for Swagger, as shown in this example:

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import springfox.documentation.builders.PathSelectors;
import springfox.documentation.builders.RequestHandlerSelectors;
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 api() {
        return new Docket(DocumentationType.SWAGGER_2)
            .select()
            .apis(RequestHandlerSelectors.basePackage("com.example.controller"))
            .paths(PathSelectors.any())
            .build();
    }
}
        

This configuration enables Swagger for your Spring Boot application and specifies which packages to include in the documentation.

Using Swagger UI

Once Swagger is configured, you can access the Swagger UI to interact with your APIs and view the documentation. Simply run your Spring Boot application and visit http://localhost:8080/swagger-ui.html in your web browser. You'll see a user-friendly interface for exploring and testing your APIs.

Customizing API Documentation

Swagger allows you to customize the documentation for your APIs by adding annotations to your controller methods. For example, you can document request and response parameters using Swagger annotations like @ApiParam and @ApiResponse.

Conclusion

Swagger is a powerful tool for documenting and testing RESTful APIs in Spring Boot applications. This guide covered how to add Swagger to your project, configure it, and use Swagger UI to explore and interact with your APIs. With Swagger, you can improve the quality and usability of your API documentation.