code: public Map getMapByIdService4text(String id, String tableName, String colName){
  		Map data=getInfoByIdService(id,tableName);
  		if(data==null){
  			return null;
  		}
  		String dataStr=(String) data.get(colName);
  		if(dataStr==null || "".equals(dataStr)){
  			dataStr="{}";
  		}
  		Gson gson = new Gson();
  		Map dataMap=gson.fromJson(dataStr,Map.class);
  		return dataMap;
  	}
docs: 20180605 ning