Q:

How to pass dynamic value to a JSON String

I have constructed a JSON String this way , but cannot able to pass dynamic values to it 
String input = "{\r\n" + 
                    "    \"Level\": 0,\r\n" + 
                    "    \"Name\": \"String\",\r\n" + 
                    "    \"msgName\": \"String\",\r\n" + 
                    "    \"ActualMessage\": \"String\",\r\n" + 
                    "    \"TimeStamp\": \"/Date(-62135596800000-0000)/\"\r\n" + 
                    "}" ;

String message = "this is value  want to pass to the ActualMessage attribute " ;

I need to pass dynamic value to the ActaulMessage atribute 

Please tell me how ?
i have tried number of trial and errors but couldn't able to succeed. 

A:

Use string concatenation. 
String message = "this is value  want to pass to the ActualMessage attribute " ;
String input = "{\r\n" + 
               "\"Level\": 0,\r\n" + 
               "\"Name\": \"String\",\r\n" + 
               "\"msgName\": \"String\",\r\n" + 
               "\"ActualMessage\": \"" + message + "\",\r\n" + 
               "\"TimeStamp\": \"/Date(-62135596800000-0000)/\"\r\n" + 
               "}" ;

