Provide sample value for request parameter in Swagger

For Spring Boot users, assuming you've a REST method, accepting json body, but for some reasons doesn't explicitly uses @RequestBody. Follow below steps to generate proper Swagger documentation

Update SpringFox configuration bean for additional model

@Bean
public Docket apiDocket() {
     return new Docket(DocumentationType.SWAGGER_2)
             // ...
             .additionalModels(new TypeResolver().resolve(YourRequestModel.class));
}

Update controller API for @ApiImplicitParams

@PostMapping("/your-api")
@ApiOperation(value = "brief description", notes = "Greater details come here")
@ApiImplicitParams({
   @ApiImplicitParam(paramType = "header", name = "x-locale", example = "en"),
   @ApiImplicitParam(paramType = "body", dataType = "YourRequestModel")
})
public YourResponsetModel processRequest() {
   // ...
   return null;
}

This will generate us Swagger with an optional header x-locale, and body of type YourRequestModel.

Unfortunately you cannot provide an sample or example value for atomic parametera (String, Number, ...).

You can only provide an example if the parameter is an object with a schema, you only have to add an example property to the property description:

properties:
  firstName:
    description: first name
    type: string
    example: John

As a last resort you could add an example value in the parameter's description (value in the ApiImplicitParam annotation).

    @ApiImplicitParam(
            name = "message", 
            value = "Message that is sent to the method. Example: value", 
            required = true, 
            dataType = "string", 
            paramType = "body"
    )