REST Mocking with Query Parametr

Open the request action.

Change the Dispatch dropdown to SCRIPT

You should then be able to script something like this: (actual working example from one of my mock services)

// Match based on query parameter
def queryString = mockRequest.getRequest().getQueryString()
log.info "QueryString: " + queryString

def response

if (queryString !=null) {
	String[] fields = queryString.split('/&')
	fields.each
	{
		// Split each query string field into its key and value
		String[] kvp = it.split('=');
		def key = kvp[0];
		def value = kvp[1] ;

		// Change the response depending on the value of nrd:AreaCode
		if( key == "nrd:AreaCode" )
		{
			if( value == "7A1" )
			{
				// return list of BCU GP Practices
				response = "Response - GP Practices - BCU"
			}
			else if( value == "7A2" )
			{
				// return list of Hywel Dda GP Practices
				response = "Response - GP Practices - Hywel Dda"
			}
		}
	}
}

if (response != null) 
{
	log.info( "response: " + response)
	return response
}

Apologies in advance regarding coding conventions / style. I am not a Groovy expert but I thought a working example would be helpful