Build Spring Boot POST, PUT, and GET Endpoints

Overview

In a retail banking system, you need to expose a RESTful API for managing customer bank accounts using Spring Boot. Implement the controller, request/response DTOs, and exception handling for creating, retrieving, and updating bank accounts.

Requirements

1. Data Contract

Define a BankAccount representation with the following fields:

• id (Long, auto-generated)
• accountNumber (String, 10 digits, unique, immutable)
• accountHolderName (String, required, 2–100 characters)
• accountType (Enum: CHECKING, SAVINGS)
• balance (BigDecimal, must be non-negative)
• status (Enum: ACTIVE, FROZEN, CLOSED)

2. Endpoints

Implement an AccountController mapped to /api/v1/accounts:

• POST /api/v1/accounts
  • Accepts a valid creation payload.
  • Returns HTTP 201 Created with the created resource and a Location header pointing to the new resource URI.
  • Rejects invalid payloads with HTTP 400 Bad Request.
• GET /api/v1/accounts/{id}
  • Returns HTTP 200 OK with the account details.
  • Returns HTTP 404 Not Found if the account does not exist.
• GET /api/v1/accounts
  • Supports an optional query parameter status (e.g., ?status=ACTIVE).
  • Returns HTTP 200 OK with a list of matching accounts.
• PUT /api/v1/accounts/{id}
  • Performs a full replacement/update of the mutable fields (accountHolderName, status). Note that accountNumber and balance cannot be updated through this endpoint.
  • Returns HTTP 200 OK on success, or HTTP 404 Not Found if the ID does not exist.

3. Error Handling & Testing

• Provide a global exception handler (@RestControllerAdvice) returning a consistent error payload with timestamp, status, error, and message.
• Write a unit/slice test using @WebMvcTest(AccountController.class) and MockMvc verifying the POST endpoint validation failure and success response.