RESTful (Representational State Transfer) is an architectural style for building web services that communicate over HTTP(S) using standard methods, such as GET, POST, PUT, DELETE, etc. It is an alternative to other web service architectures such as SOAP (Simple Object Access Protocol).
The RESTful API design in Java follows a set of principles, known as the Richardson Maturity Model, which defines a set of levels for RESTful APIs. The levels are:
Level 0: The system uses HTTP as a transport mechanism for remote interactions.
Level 1: The system uses HTTP methods (GET, POST, PUT, DELETE) for different types of interactions.
Level 2: The system uses HTTP status codes to indicate the result of an operation.
Level 3: The system uses HATEOAS (Hypermedia as the Engine of Application State) to enable the client to dynamically discover and interact with available resources.
The following are some key design principles of a RESTful API in Java:
Resource-Oriented: RESTful API design is resource-oriented, which means that every resource is uniquely identified by a URI (Uniform Resource Identifier). The resource can be anything that needs to be exposed through the API, such as a user, a product, or an order.
CRUD Operations: RESTful APIs use HTTP methods to perform CRUD (Create, Read, Update, and Delete) operations on resources. GET method is used to retrieve a resource, POST method is used to create a new resource, PUT method is used to update an existing resource, and DELETE method is used to delete a resource.
Stateless: RESTful APIs are stateless, which means that the server does not store any client context. Each request from the client contains all the necessary information needed to complete the request.
Uniform Interface: RESTful APIs use a uniform interface to access resources. This interface is composed of four elements: the resource URI, the HTTP method, the representation of the resource, and the HTTP status code.
Cacheable: RESTful APIs are designed to be cacheable, which means that responses from the server can be cached on the client side for future use.