日期类的使用

package cn.zhang.test;

import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;

/**
 * 测试日期类的使用
 * @author 张涛
 *
 */
public class TestCalendar {
    public static void main(String[] args) {
        
        /*获得日期相关的元素*/
        Calendar c1 = new GregorianCalendar(2019,8,20,16,30,00);
        int year = c1.get(Calendar.YEAR);
        int month = c1.get(Calendar.MONTH);
        int day = c1.get(Calendar.DATE);//也可以使用DAY_OF_MONTH
        int weekday = c1.get(Calendar.DAY_OF_WEEK);//星期几
        System.out.println(year);
        System.out.println(month);
        System.out.println(day);
        System.out.println("周" + weekday);
        printCalendar(c1);
        
        /*设置日期相关的元素*/
        Calendar c2 = new GregorianCalendar();//默认获得当前日期
        System.out.println(c2);
        c2.set(Calendar.YEAR, 2020);
        System.out.println(c2);
        
        /*日期的计算*/
        Calendar c3 = new GregorianCalendar();
        c3.add(Calendar.YEAR, 100);
        System.out.println(c3);
        
        /*日期对象和时间对象的转化*/
        Calendar c4 = new GregorianCalendar();
        Date d = c4.getTime();//日期对象转时间对象
        System.out.println(d);
        
        Calendar c5 = new GregorianCalendar();
        c5.setTime(new Date());
        System.out.println(c5);
    }
    
    public static void printCalendar(Calendar c) {
        //打印时间 格式xxxx年xx月xx日xx时xx分xx秒
        int year = c.get(Calendar.YEAR);
        int month = c.get(Calendar.MONTH)+1;
        int date = c.get(Calendar.DATE);
        int week = c.get(Calendar.DAY_OF_WEEK)-1;
        String weekday = week == 0?"日":week+"";
        int hour = c.get(Calendar.HOUR);
        int minute = c.get(Calendar.MINUTE);
        int second = c.get(Calendar.SECOND);
        
        System.out.println(year+"年"+month+"月"+date+"日"+hour+"时"+minute+"分"+second+"秒"+" 周"+ weekday);
    }
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
}