ajax请求spring mvc Controller返回的json中的引号被转义

UserShowDto showDto = new UserShowDto(show);
//JSONObject json = JSONObject.fromObject(showDto);
map.put("status", SystemConstants.SYSTEM_SUCCESS);
//JSONObject jo = new JSONObject();
//jo.put("name","mical");
map.put("showDto", showDto);
System.out.println(map);
//String str = "'hello'";
//System.out.println(json);
return map;
success : function (result){
var str = JSON.stringify(result);
lert(str);