1.Calendar和Date的轉(zhuǎn)化
(1) Calendar轉(zhuǎn)化為Date
Calendar cal=Calendar.getInstance();
Date date=cal.getTime();
(2) Date轉(zhuǎn)化為Calendar
Date date=new Date();
Calendar cal=Calendar.getInstance();
cal.setTime(date);
3,如果日期為空,默認(rèn)一個(gè)日期
cal.set(1990,01,01);