RestResource GET with multiple parameters
HTTP GET defines data as a series of query parameters in the URI itself. For example, here’s a URI:
https://na8.salesforce.com/services/apexrest/FieldCase?companyName=GenePoint
So your code will be like
@RestResource(urlMapping='/Revenues/*)
@HttpGet
global static List<Case> getOpenCases() {
String accountId = RestContext.request.params.get('accountId');
String accountId = RestContext.request.params.get('serviceId');
Creating REST APIs using Apex REST
Or you can parse the URl as well
@HttpGet
global static Account doGet() {
RestRequest req = RestContext.request;
RestResponse res = RestContext.response;
String accountId = req.requestURI.substring(req.requestURI.lastIndexOf('/')+1);
Apex REST Basic Code Sample