gistfile1.txt

@HttpPost
    global static string postwebserviceutil() {
    
        //Extracting the data from the JSON HTTP request object sent from Timetrade
        
        RestRequest req = RestContext.request;
        RestResponse res=RestContext.response;
        Blob body=req.requestBody;
        String jsonToParse=body.toString();  
        
        jsonToParse=jsonToParse.replace('class','classx'); //replacing if any keyword found
        jsonToParse=jsonToParse.replace('limit','limitx');
        jsonToParse=jsonToParse.replace('_externalIDs','externalIDs');    
            
        
        //Deserializing the data sent into concrete SFDC objects
        DeserialisedClass var =(DeserialisedClass)JSON.deserialize(jsonToParse,DeserialisedClass.class);
        
        system.debug('value'+var );

    }

}