当前时间往前后推算

public static void main(String[] args) {

    SimpleDateFormat sdf =  new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    Date nowDate = new Date();
    Calendar calendar = Calendar.getInstance();
    calendar.setTime(nowDate);
    Date updateDate1 = calendar.getTime();
    System.out.println("当前时间="+sdf.format(updateDate1));


    calendar.set(Calendar.DATE, - 180);
    Date updateDate4 = calendar.getTime();
    System.out.println("往前推180天的时间="+sdf.format(updateDate4));

    //calendar.setTime(updateDate4);
    calendar.set(Calendar.DATE, + 3);
    Date updateDate5 = calendar.getTime();
    System.out.println("180往后推3天的时间="+sdf.format(updateDate5));


}