How to connect React.js with Spring Boot?

@lily 

To connect React.js with Spring Boot, follow the steps below:

1. Set up a new Spring Boot project: Start by creating a new Spring Boot project using your preferred IDE or by using Spring Initializer. Make sure to include the necessary dependencies for building a REST API.
2. Set up a new React.js project: Create a new React.js project using create-react-app or any other preferred method. This will set up the basic structure and dependencies needed for a React.js project.
3. Create a REST API: In your Spring Boot project, create the necessary controllers, services, and repositories to build the REST API. These components should handle the logic and data retrieval, manipulation, and persistence.
4. Enable CORS: By default, Spring Boot's security configuration may block cross-origin resource sharing (CORS) requests. To allow your React.js frontend to communicate with the Spring Boot backend, you need to enable CORS configuration. You can do this by adding the @CrossOrigin annotation to your REST controller classes or by configuring CORS globally using a WebMvcConfigurer bean.
5. Build the React.js frontend: In your React.js project, create the necessary components, forms, and views required for your frontend application. Use Axios or any other HTTP library to make API calls to your Spring Boot backend.
6. Connect React.js with Spring Boot: In your React.js project, use the base URL of your Spring Boot backend to connect to the API endpoints. You can define this base URL as a global variable or use environment variables to make it configurable based on the deployment environment.
7. Test the integration: Start your Spring Boot backend server, and then run your React.js frontend application. Verify that your frontend can communicate with the backend by accessing the API endpoints and displaying the retrieved data or performing CRUD operations.
8. Deploy your application: Once you have tested the integration, build and deploy your Spring Boot backend and React.js frontend separately or together, depending on your deployment architecture.

By following these steps, you can connect React.js with Spring Boot and build a full-stack web application.