Spring boot & Paypal Payment Integration

Configure a PayPal config class in a config package to supply client id, client secret, and mode via application properties, and expose an API context bean using sandbox mode.

Create a new PayPal app in the developer dashboard to generate PayPal client ID and client secret, switch between sandbox and live, and copy credentials for integration.

Create a PayPal service class in a Spring Boot project, move it to a package named PayPal, inject the API context with Lombok's required-args constructor, and begin implementing payment methods.

Implement a PayPal payment creation method that builds amount, transaction, payer, and redirect URLs, formats totals by locale, and returns the payment via the API context.

Implement the execute payment method in Spring Boot PayPal integration by creating a payment object with the payment ID and a payment execution with the payer ID, then execute it.

Create a PayPal controller in a Spring Boot MVC app using Thymeleaf, inject the PayPal service via a required-args constructor, and define the controller methods within the same application.

Implement the index method with a get mapping for the root path and return the public home string, representing the index.html page.

Implement a Spring Boot create payment endpoint for PayPal integration, building a PayPal payment object, extracting the approval URL, and redirecting users to PayPal with error handling.

Implement the PayPal payment success flow in a Spring Boot app by exposing a get /payment/success endpoint, accepting paymentId and payerId, executing the payment, and routing to the success view.

Create a get mapping for payment cancel, match the URL, and return the payment cancel view to complete the post-payment flow and the payment error page.

Duplicate the existing payment cancel flow to implement a payment error page in the PayPal controller, renaming the method to error.

Create the home page using thymeleaf and html, wire a bootstrap-styled index.html, and implement a post form that posts to /payment/create for PayPal integration.

Duplicate the index page to create payment-success.html, remove the form, preserve the title and a back-to-home link, then proceed to implement the cancel payment.

Create a dedicated payment cancel page by duplicating the existing payment success page, updating the text to 'payment canceled', and adding a back-to-home button.

Ensure HTML template names match and avoid typos, navigate to index.html with command or control-click, and test payment success, cancel, and error pages in your Spring Boot and PayPal integration.

Test the PayPal payment flow in a spring boot app by running the app, using sandbox PayPal, and validating success, cancel, and error paths with redirects and parameters.

Add a PayPal payment form in the index.html with method, amount, currency, and description fields using Thymeleaf and Bootstrap. Configure default USD and read-only method input to guide integration.

Enhance the PayPal controller by adding request params for amount, currency, and method, and include optional inputs for description and intent. Test the application by running the project.

Test the new changes in a Spring Boot and PayPal payment integration by validating the read-only payment method, euros amount, and automatic currency conversion on PayPal redirection.