HTTP PATCH variants in Spring MVC

This sample project contains variants of implementing HTTP PATCH in Spring MVC.

• Build the sample -> ./gradlew clean build
• Run the server -> ./gradlew bootRun
• OpenAPI documentation is available at http://localhost:8080/swagger-ui.html

The service contains one resource Entity and APIs to create, read and update Entity resources.

Different PATCH variants demonstrated:

• Copy only non null attributes from request body:
  • In this mode, only non null attributes from the request body are patched.
  • Downside of this approach is there is no way to reset already set attributes.
  • Use API PATCH /api/entities/copy-nonull/{id}
• JSON Merge Patch:
  • In this mode, all attributes from the request body are patched.
  • This is as per RFC 7396: JSON Merge Patch
  • If the caller wants to reset an attribute, then specifying the attribute as null would result in reset of that attribute.
  • Use API PATCH /api/entities/{id}