Main part is serving routes. The class
spark.Spark (Javadoc)
defines a static method for every HTTP verb:
The first argument is the path. The path is the path after the host name (or part of it). The path can contain parameters
(e.g. /book/:id/edit) and wildcards (/product/*).
An object that implements Route or TemplateViewRoute is also always an argument. Typically, a route is defined as
(req, res) -> code_returning_the_response, where req is the Request object and res is the
Response object. The return value is an Object. Often it is HTML or JSON. If the route wants to return nothing
you can return null.
Use the HTTP verb methods with a ResponseTransformer argument if you want to transform the response object (to a String). A typical use case is that a route returns a data object and a JsonTransformer transforms this object into a JSON string.
import com.google.gson.Gson;
public class JsonTransformer implements ResponseTransformer {
private static final Gson gson = new Gson();
@Override
public String render(Object model) {
return gson.toJson(model);
}
}
If you specify a MIME type as the Accept Type String, HTTP verb methods will only be called if the caller has also specified this MIME type in the Accept attribute of the HTTP request.