[REQ] Generate Spring HTTP Interface with configurable URL placeholder via Spring properties

Description

This feature request proposes an enhancement to the OpenAPI Generator Java spring-http-interface. It aims to introduce the ability to generate interfaces annotated with @HttpExchange (Spring Framework 3) where the field url or value attribute can be configured using a placeholder with a default value (the path defined in the API specification).

This is a snippet of the current mustache template:

    @HttpExchange(
        method = "{{{httpMethod}}}",
        value = "{{{path}}}",
        accept = { {{#vendorExtensions.x-accepts}}"{{.}}"{{^-last}}, {{/-last}}{{/vendorExtensions.x-accepts}} }{{#vendorExtensions.x-content-type}},
        contentType = "{{{vendorExtensions.x-content-type}}}"{{/vendorExtensions.x-content-type}}
    )

Proposed Implementation

Update the mustache template to add a placeholder with a default value, for example:

    @HttpExchange(
        method = "{{{httpMethod}}}",
        value = "${openapi.{{operationId}}.base-path:{{path}}}",
        accept = { {{#vendorExtensions.x-accepts}}"{{.}}"{{^-last}}, {{/-last}}{{/vendorExtensions.x-accepts}} }{{#vendorExtensions.x-content-type}},
        contentType = "{{{vendorExtensions.x-content-type}}}"{{/vendorExtensions.x-content-type}}
    )

Creating a custom version of this template embedded into my application is not the best solution.

Does anyone know a way to achieve what I'm asking for using the current template?

Example

Snippet of API definition example.yaml

paths:
  /users:
    get:
      summary: Get all users
      operationId: getUsers
  /products/{productId}:
    get:
      summary: Get a product by ID
      operationId: getProductById

Generated ExampleService.java

public interface ExampleService {

  @HttpExchange(
      method = "GET",
      value = "${openapi.getUsers.base-path:/users}",
      accept = { "application/json" }
  )
  ResponseEntity<List<User>> getUsers();

  @HttpExchange(
      method = "GET",
      value = "${openapi.getProductById.base-path:/products/{productId}",
      accept = { "application/json" }
  )
  ResponseEntity<Product> getProductById(@PathVariable String productId);

}

Snippet of application.properties file

openapi.getUsers.base-path=/new/path/to/users
openapi.getProductById.base-path=/new/path/to/products/{productId}

Benefis

• Flexibility: this feature allows for dynamic configuration of API paths, potentially from environment variables or configuration files
• Maintainability: separating the path definition from the annotation improves code maintainability and reduces duplication

I hope the OpenAPI Generator maintainers find this feature useful. I would be happy to proceed with implementation. Thank you.

Start with modules/openapi-generator/src/main/resources/JavaSpring/libraries/spring-http-interface/api.mustache and compare it with the example.yaml and generated ExampleService.java shown in the issue. Verify the generated @HttpExchange values support configurable Spring property placeholders while retaining the specification paths as defaults, including paths with variables such as /products/{productId}.