Net. SF. JSON. jsonexception: there is a cycle in the hierarchy!

The project uses Ajax technology, jar package is: json-lib.jar, encountered a problem related to JSON-LIB and hibernate in the development process:

Net. SF. JSON. jsonexception: there is a cycle in the hierarchy!
At net. SF. JSON. util. cycledetectionstrategy $ strictcycledetectionstrategy. handlerepeatedreferenceasobject (cycledetectionstrategy.

A circular error occurs when the primary and Foreign keys are associated.

Filter needs to be set to remove Association

 

Java

    public ModelAndView getRooms(HttpServletResponse response,@PathVariable Long hotelsid){        List<Room> roomList=roomService.findByHotelsid(hotelsid);        JsonConfig jsonConfig = new JsonConfig();        jsonConfig.setJsonPropertyFilter(new net.sf.json.util.PropertyFilter(){            @Override            public boolean apply(Object source, String name, Object value) {                if(name.equals("hotels")){                    return true;                }else{                return false;                }            }});                JSONArray json=JSONArray.fromObject(roomList,jsonConfig);                try {            PrintWriter out=response.getWriter();            out.println(json.toString());            out.flush();            out.close();        } catch (IOException e) {            e.printStackTrace();        }                return null;    }