Calendar时间接口操作

public static void main(String[] args) {
	SimpleDateFormat fmt=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

    Calendar cal = Calendar.getInstance();
    //获取时间
    System.out.println("年:" + cal.get(Calendar.YEAR));
    System.out.println("月:" + (cal.get(Calendar.MONTH) + 1));
    System.out.println("日:" + cal.get(Calendar.DAY_OF_MONTH));
    System.out.println("时:" + cal.get(Calendar.HOUR_OF_DAY));
    System.out.println("分:" + cal.get(Calendar.MINUTE));
    System.out.println("秒:" + cal.get(Calendar.SECOND));
    System.out.println("当前时间"+fmt.format(cal.getTime()));//2019-08-11 11:25:36
    // 赋值时间，注意月份下标从0开始，所以取月份要+1
    cal.set(1998, 4, 10, 23,59,59);
    System.out.println("设置后时间"+fmt.format(cal.getTime()));//1998-05-10 23:59:59
    // 或者6个字段分别进行设置，由于月份下标从0开始赋值月份要-1
    cal.set(Calendar.YEAR, 1998);
    cal.set(Calendar.MONTH, 4);
    cal.set(Calendar.DAY_OF_MONTH, 10);
    cal.set(Calendar.HOUR_OF_DAY, 00);
    cal.set(Calendar.MINUTE, 00);
    cal.set(Calendar.SECOND, 00);
    System.out.println("设置后时间"+fmt.format(cal.getTime()));//1998-05-10 00:00:00

    //年加1减1
    cal.add(Calendar.YEAR, 1);
    System.out.println("年+1:"+fmt.format(cal.getTime()));//1999-05-10 00:00:00
    cal.add(Calendar.YEAR, -1);
    System.out.println("年-1:"+fmt.format(cal.getTime()));//1998-05-10 00:00:00

    //月加1减1
    cal.add(Calendar.MONTH, 1);
    System.out.println("月+1:"+fmt.format(cal.getTime()));//1998-06-10 00:00:00
    cal.add(Calendar.MONTH, -1);
    System.out.println("月-1:"+fmt.format(cal.getTime()));//1998-05-10 00:00:00

    //天加1减1
    cal.add(Calendar.DAY_OF_MONTH, 1);
    System.out.println("天+1:"+fmt.format(cal.getTime()));//1998-05-11 00:00:00
    cal.add(Calendar.DAY_OF_MONTH, -1);
    System.out.println("天-1:"+fmt.format(cal.getTime()));//1998-05-10 00:00:00

    //时加1减1
    cal.add(Calendar.HOUR_OF_DAY, 1);
    System.out.println("时+1:"+fmt.format(cal.getTime()));//1998-05-10 01:00:00
    cal.add(Calendar.HOUR_OF_DAY, -1);
    System.out.println("时-1:"+fmt.format(cal.getTime()));//1998-05-10 00:00:00

    //分加1减1
    cal.add(Calendar.MINUTE, 1);
    System.out.println("分+1:"+fmt.format(cal.getTime()));//1998-05-10 00:01:00
    cal.add(Calendar.MINUTE, -1);
    System.out.println("分+1:"+fmt.format(cal.getTime()));//1998-05-10 00:00:00
    //秒加1减1
    cal.add(Calendar.SECOND, 1);
    System.out.println("秒+1:"+fmt.format(cal.getTime()));//1998-05-10 00:00:01
    cal.add(Calendar.SECOND, -1);
    System.out.println("秒-1:"+fmt.format(cal.getTime()));//1998-05-10 00:00:00
}