I have a service that does some work on an HttpServletRequest object, specifically using the request.getParameterMap and request.getParameter to construct an object.
Here it is how to use MockHttpServletRequest:
// given
MockHttpServletRequest request = new MockHttpServletRequest();
request.setServerName("www.example.com");
request.setRequestURI("/foo");
request.setQueryString("param1=value1¶m");
// when
String url = request.getRequestURL() + '?' + request.getQueryString(); // assuming there is always queryString.
// then
assertThat(url, is("http://www.example.com:80/foo?param1=value1¶m"));