Java获取一个小时前的时间

public static void getTimeOneHourBefore() {
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.HOUR_OF_DAY,
calendar.get(Calendar.HOUR_OF_DAY) - 1);
SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
System.out.println("一个小时前的时间：" + df.format(calendar.getTime()));
System.out.println("当前的时间：" + df.format(new Date()));
}