add more data conversion strategies

  public <T> T getFieldValue(Class<T> clazz, Object value){

    if (value ==  null){

      return null;

    }

    if (clazz.isAssignableFrom(value.getClass())){

      return (T)value;

    }

    try{

      if (value instanceof Number) {

        if (clazz == int.class || clazz == Integer.class){

          value = ((Number)value).intValue();

        } else if (clazz == double.class || clazz == Double.class){

          value = ((Number)value).doubleValue();

        } else if (clazz == long.class || clazz == Long.class){

          value = ((Number)value).longValue();

        } else if (clazz == String.class){

          value = ((Number)value).toString();

        } else {

          throw new RuntimeException("Not expecting value: " + value.getClass());

        }

      } else {

        throw new RuntimeException("Not expecting value: " + value.getClass());

      }

      return (T)value;

    } catch (Exception e){

      throw new RuntimeException(e);

    }

  }