Date类和Calendar类 一、 import java.util.Calendar; import java.util.Date; import java.util.GregorianCalendar;
public class DateTest1 {
public static void main(String[] args) {
//Calendar转化为Date
// Calendar cal=Calendar.getInstance();
//Date date=cal.getTime();
//Date转化为Calendar 日期转换为日历
Date now=new Date();
System.out.println(now.getYear());
System.out.println(now.getDate());
System.out.println(now.getHours());
System.out.println(now.getSeconds());
System.out.println(now.getClass());
Calendar cal=Calendar.getInstance();//calendar是抽象类，不能new
System.out.println(cal.getClass());//java.util.GregorianCalendar
// GregorianCalendar gc=new GregorianCalendar();
// gc.setTime(now);
// System.out.println(gc.get(Calendar.YEAR));
cal.setTime(now);
//cal.getTime();
int year=cal.get(Calendar.YEAR);
System.out.println(year);
int month=cal.get(Calendar.MONTH);
System.out.println(month);
int week=cal.get(Calendar.DAY_OF_MONTH);
System.out.println(week);
int hour=cal.get(Calendar.HOUR);
System.out.println(hour);
System.out.println(cal.get(Calendar.DAY_OF_WEEK_IN_MONTH));
cal.set(2019, 6, 16);
Date date=cal.getTime();
System.out.println(date);
System.out.println(date.getYear());
System.out.println(date.getMonth());
System.out.println(date.getDay());
}
}
二、
import java.text.ParseException; import java.text.SimpleDateFormat; import java.util.Date; public class DateTest2 {
public static void main(String[] args) {
// TODO Auto-generated method stub
Date now=new Date();
//SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
SimpleDateFormat sdf=new SimpleDateFormat("yyyy年MM月dd日");//格式要一样
String s=sdf.format(now);
System.out.println(s);
Date date;
try {
date = sdf.parse("2019-06-22 15:33:33");//格式要一样，不然会抛出异常
System.out.println(date);
} catch (ParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
