JAVA根据时间增加1天

String time = "2021-12-1"; //指定时间
int day = 30;//指定增加天数
SimpleDateFormat sf = new SimpleDateFormat("yyyy-MM-dd");
Date timeNow = sf.parse(time);
Calendar c = Calendar.getInstance();
c.setTime(timeNow); 
System.out.println("当前日期:"+sf.format(timeNow));
c.add(Calendar.DAY_OF_MONTH, day);
System.out.println("增加后日期:"+sf.format(c.getTime()));