How to map in same business object using different input object?

Right Now in my application input data(City data) coming from database. I follow the below procedure for processing the input. - read the data from database and create the CityDTO object(Class=CityDTO) - map DTO to business object (CityBO)

But now, Client will send city data with Json file using webservice. Now i have CityJson object(Class = CityJSon) and i want to map CityJSon to CityBO

Two different input object and wanted to map in same business object. How can i achieve this so that if in future client add more input type then my application code must be maintained.?