YAML is a superset of JSON. This means you can use JSON syntax for objects and arrays within a YAML document.

In your first example, you can just remove the | after the value: to keep the example value as an object.

The following are equivalent:

examples:
  singlePet:
    summary: Single pet
    description: A request containing a single pet
    value:
      {
        "pets" : [
          {
            "petType" : "DOG",
            "name" : "Ben"
          }
        ]
      }

examples:
  singlePet:
    summary: Single pet
    description: A request containing a single pet
    value:
      pets:
      - petType: DOG
        name: Ben

Alternatively, you can use externalValue to point to an external file containing sample JSON.

examples:
  singlePet:
    summary: Single pet
    description: A request containing a single pet
    externalValue: 'https://api.example.com/docs/examples/pet.json'

We have used lately springdoc-openapi java library. It helps automating the generation of API documentation using spring boot projects.

It automatically deploys swagger-ui to a spring-boot application Documentation will be available in HTML format, using the official [swagger-ui jars]:

The Swagger UI page should then be available at http://server:port/context-path/swagger-ui.html and the OpenAPI description will be available at the following url for json format: http://server:port/context-path/v3/api-docs

• server: The server name or IP
• port: The server port
• context-path: The context path of the application

Documentation can be available in yaml format as well, on the following path: /v3/api-docs.yaml. (to convert into yaml) Add the library to the list of your project dependencies (No additional configuration is needed)

 <dependency>
      <groupId>org.springdoc</groupId>
      <artifactId>springdoc-openapi-ui</artifactId>
      <version>1.2.3</version>
  </dependency>