Empty query parameters should not be shown in build URI.

MvcUriComponentsBuilderApplication.java

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.servlet.mvc.method.annotation.MvcUriComponentsBuilder;

@SpringBootApplication
@Controller
public class MvcUriComponentsBuilderApplication {

    public static void main(String[] args) {
        SpringApplication.run(MvcUriComponentsBuilderApplication.class, args);
    }

    @RequestMapping("/")
    @ResponseBody
    public String index(@RequestParam(value = "q", defaultValue = "") String query, Model m) {
        return MvcUriComponentsBuilder.fromMappingName("UBA#index").build();
    }
}

I would expect that optional query parameters of a controller method are not rendered in a build URI. However the current implementation renders these parameters without equal sign and value. Normally this isn't a problem but when using such an URI in a GET form this leads to problems...