OpenAPI Specification to Java Client SDK Generator

This project helps generate an API Wrapper (SDK) for any API based on its OpenAPI Specification. The generated module provides a structured and easy-to-use Java client for interacting with the API, reducing the need to manually handle HTTP requests, responses, and error handling.

Features

• Automatic API Client Generation – Converts an OpenAPI Specification into a ready-to-use Java SDK.
• Supports OkHttp & Retrofit – Choose between OkHttp (low-level control) or Retrofit (high-level API client).
• Handles Request & Response Parsing – Uses Gson for automatic JSON serialization.
• Customizable Dependencies – Select dependencies dynamically via CLI.
• Improved API Integration – No need to manually construct API requests.

Why Use an API Wrapper?

When developing applications, directly handling HTTP requests, retries, response parsing, and API errors can lead to unnecessary complexity. By using a generated API Wrapper (SDK):

• API requests and responses are managed within a structured Java client.
• Business logic remains separate from network-related concerns.
• Handling retries, authentication, and error handling becomes standardized.

Installation

Prerequisites

• Java 17 or later
• Maven
• OpenAPI YAML file (named openapi.yaml)

Build and Install

1. Clone the repository:

   git clone https://github.com/your-username/openapi-java-parser.git
   cd openapi-java-parser

2. Build the Project:

   mvn clean package

3. The compiled JAR will be available at:

   target/openapi-java-parser-{latest-version}.jar
   

Usage

Video Link

You can visit our youtube channel to check the working of it: https://youtu.be/nEoP3hjDhIQ

Running the CLI Tool

To generate an API wrapper, run the JAR with the following options:

java -jar target/openapi-java-parser-{latest-release-version}.jar
-spec path/to/openapi.yaml 
-output path/to/output_directory
-dependencies okhttp,jackson,slf4j
-type okhttp

CLI Options

Option	Description
-s, --spec	Path to the OpenAPI YAML file
-o, --output	Output directory for the generated SDK
-d, --dependencies	Comma-separated list of dependencies (e.g., retrofit,jackson,okhttp)
-t, --type	Type of API wrapper (retrofit or okhttp)

Verifying the Generated SDK

Once the SDK is generated, navigate to the output directory:

ls output

It should contain:

generated-sdk
├── pom.xml
├── src/main/java/com/example/
│   ├── MainApplication.java
│   ├── api/
│   │   ├── ApiWrapper.java
│   │   ├── RetrofitAPIClient.java (For Retrofit)
│   │   ├── OkHttpAPIClient.java (For OkHttp)

Running the Generated SDK

1. Navigate to SDK Directory:

   cd generated-sdk

2. Build the SDK

   mvn clean package

3. Run the SDK:

   mvn exec:java -Dexec.mainClass="com.example.MainApplication"

Contributing

Contributions are welcome. If you would like to contribute, follow these steps:

1. Fork the repository
2. Create a new branch (feature/new-feature)
3. Commit your changes (git commit -m 'Add new feature')
4. Push to the branch (git push origin feature/new-feature)
5. Open a pull request

Developer Contacts

• Email: krishjaiswal1701@gmail.com
• Linkedin: https://linkedin.com/in/jaiswal-krish