@Override
	public String toString() {
		if(useJdkToStringStyle){
			return super.toString();
		}
		return toString(this.timeZone);
	}
@Test
	public void toStringTest() {
		DateTime dateTime = new DateTime("2017-01-05 12:34:23", DatePattern.NORM_DATETIME_FORMAT);
		assertEquals("2017-01-05 12:34:23", dateTime.toString());

		String dateStr = dateTime.toString("yyyy/MM/dd");
		assertEquals("2017/01/05", dateStr);
	}