Step by step explanation of this project is in my blog.
If you are not familiar with the Unit Testing in Spring Boot, I advice you to read my article on Medium.
HTTP verbs are one of the most popular interview questions. I wanted to do a small project to help Java developers succeed in their interviews.
The most-commonly-used HTTP verbs are POST, GET, PUT, PATCH, and DELETE. These are create, read, update, and delete (or CRUD) operations, respectively. There are a number of other verbs, too, but are utilized less frequently.[1]
| HTTP Verb | CRUD | Entire Collection (e.g. /customers) | Specific Item (e.g. /customers/{id}) |
|---|---|---|---|
| POST | Create | 201 (Created), 'Location' header with link to /customers/{id} containing new ID. | 404 (Not Found), 409 (Conflict) if resource already exists.. |
| GET | Read | 200 (OK), list of customers. Use pagination, sorting and filtering to navigate big lists. | 200 (OK), list of customers. Use pagination, sorting and filtering to navigate big lists. |
| PUT | Update | 405 (Method Not Allowed), unless you want to update/replace every resource in the entire collection. | 200 (OK) or 204 (No Content). 404 (Not Found), if ID not found or invalid. |
| PATCH | Update/Modify | 405 (Method Not Allowed), unless you want to modify the collection itself. | 200 (OK) or 204 (No Content). 404 (Not Found), if ID not found or invalid. |
The HTTP GET method is used to read (or retrieve) a representation of a resource. In the “happy” (or non-error) path, GET returns a representation in XML or JSON and an HTTP response code of 200 (OK). In an error case, it most often returns a 404 (NOT FOUND) or 400 (BAD REQUEST).
GET http://www.example.com/customers/12345
GET http://www.example.com/customers/12345/orders
GET http://www.example.com/buckets/sample
The POST verb is most-often utilized to create new resources. It is also possible to create a new resource for a specific parent. In this case, POST takes care of associating the new resource with the parent, assigning an ID (new resource URI).
POST http://www.example.com/customers
POST http://www.example.com/customers/12345/orders
PUT is most-often utilized for update capabilities,PUT-ing to a known resource URI with the request body containing the newly-updated representation of the original resource.
PUT http://www.example.com/customers/12345
PUT http://www.example.com/customers/12345/orders/
PUT http://www.example.com/buckets/secret_stuff
POST and PUT differs in idempotence and resource id allocation. Remember, this is the default interview question for http verbs.
In the context of REST APIs, when making multiple identical requests has the same effect as making a single request – then that REST API is called idempotent [2]. Making N POST requests will result in N new resources on the server and contain the same information. However, making N PUT requests will result in only 1 resource on the server. The first request will update the resource; then rest N-1 requests will just overwrite the same resource.
PUT can be used to create a resource in the case where the resource ID is chosen by the client instead of by the server. When we create a new resource with POST, the server determines the resource ID.
PATCH is used for modify capabilities. The PATCH request only needs to contain the changes to the resource, not the complete resource.
PATCH http://www.example.com/customers/12345
PATCH http://www.example.com/customers/12345/orders/98765
PATCH http://www.example.com/buckets/secret_stuff
- https://www.restapitutorial.com/lessons/httpmethods.html
- https://restfulapi.net/idempotent-rest-apis/
- https://nullbeans.com/using-put-vs-patch-when-building-a-rest-api-in-spring/
- https://www.javadevjournal.com/spring/rest/http-put-vs-http-patch-in-a-rest-api/
- https://www.logicbig.com/tutorials/spring-framework/spring-web-mvc/http-patch-test.html