oop 日期类，日历类，日期格式

/*
 * 日期格式 类   SimpleDateFormat
 * 日期类   Date
 * 日历类   Calendar
 */
import java.text.SimpleDateFormat;
import java.util.Date;


public class MyDate {
	public static void main(String[] args) {
		Date date=new Date();
		System.out.println(date);
		System.out.println(date.getYear()+1900);
		System.out.println(date.getMonth());
		System.out.println(date.getDate());
		System.out.println(date.getHours());
		System.out.println(date.getSeconds());
		
		
		SimpleDateFormat sdf=new SimpleDateFormat("yyyy年MM月dd日 HH:mm:ss: EEE");
		System.out.println(sdf.format(date));
		//format  格式 使格式化
	}
}

/*
 * Calendar  日历类
 */

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

public class MyCalendar {
public static void main(String[] args) {
Calendar cd=Calendar.getInstance();
/*
* 
      Calendar.getInstance()的解释
      Gets a calendar using the default time zone and locale.
      The Calendar returned is based on the current time in the default time zone with the default FORMAT locale.
      Returns:a Calendar.
*/
System.out.println(cd);
System.out.println(cd.get(Calendar.YEAR));
System.out.println(cd.get(Calendar.MONTH)+1);//0~11表示 1~12月份
System.out.println(cd.get(Calendar.DATE));
System.out.println(cd.get(Calendar.HOUR));
System.out.println(cd.get(Calendar.MINUTE));
System.out.println(cd.get(Calendar.SECOND));

//long num=14702311004531;
//System.out.println(new Date(num));

//求20分钟后的日期
cd.add(Calendar.MINUTE,20 );
System.out.println(cd);

//将一个日历转成一个Date
Date date=cd.getTime();
SimpleDateFormat sdf=new SimpleDateFormat("yyyy年MM月dd日 HH:mm:ss:SS: EEE");
System.out.println(sdf.format(date));

//2016-08-03 21:46 2016-08-05 11:23 求出这；两个时间之间相差的小时  以及相差的分钟
SimpleDateFormat sdf1=new SimpleDateFormat("yyyy-MM-dd HH:mm");//指定给定的日期字符串格式

try {
Date d1=sdf1.parse("2016-08-03 21:46");//将给定的字符串变成一个日期对象
Date d2=sdf1.parse("2016-08-05 11:23");
System.out.println(Math.abs(Math.floor(d1.getTime()-d2.getTime())/1000/60/60));
System.out.println(Math.abs(Math.floor(d1.getTime()-d2.getTime())/1000/60));


//将日期转化成日历
cd.setTime(d2);
System.out.println(cd);


} catch (ParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

}
}