Adding error handling
Handling errors in a structured and well-thought-out way is essential in a microservice landscape where a large number of microservices communicate with each other using synchronous APIs, for example, using HTTP and JSON. It is also important to separate protocol-specific handling of errors, such as HTTP status codes, from the business logic.
It could be argued that a separate layer for the business logic should be added when implementing the microservices. This should ensure that business logic is separated from the protocol-specific code, making it easier both to test and reuse. To avoid unnecessary complexity in the examples provided in this book, we have left out a separate layer for business logic, so the microservices implement their business logic directly in the @RestController components.
I have created a set of Java exceptions in the util project that are used by both the API implementations and the API clients, initially InvalidInputException...
