浅试Date和Calendar

时间日期处理

一、Date

从1970年1月1号8:00 开始计算

package com.bo;

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

public class DateTest {

	public static void main(String[] args) throws ParseException {
		// TODO Auto-generated method stub
		Date date = new Date();
		Date date1 = new Date(10000000000000L);//参数是长整型毫秒数 从1970年1月1号8:00 开始添加毫秒数	
		System.out.println(date);
		System.out.println(date1);
		System.out.println(System.currentTimeMillis());//当前时间毫秒数
		
		Date date2 = new Date(System.currentTimeMillis());
		System.out.println(date2);
		
		System.out.println(date.getTime());
		
		
		String dateStr = date.toString();
		String dateStr1 = date.toGMTString();
		String dateStr2 = date.toLocaleString();
		
		SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
		String dateStr3 = format.format(date);
		
		String dateStr4 = "1997-12-13 12:04:23";
		Date date3 = format.parse(dateStr4);
		
		System.out.println(dateStr);
		System.out.println(dateStr1);
		System.out.println(dateStr2);
		System.out.println(dateStr3);
		System.out.println(date3);
	}

}

二、Calendar

package com.bo;

import java.util.Calendar;

public class CalendarTest {

	//对Date类的封装强化
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Calendar c = Calendar.getInstance();
		System.out.println(c);
		System.out.println(c.getTime());//返回一个Date类型
		
		System.out.println(c.get(Calendar.YEAR));
		System.out.println(c.get(Calendar.MONTH));
		System.out.println(c.get(Calendar.DATE));
		System.out.println(c.get(Calendar.HOUR_OF_DAY));
		System.out.println(c.get(Calendar.MINUTE));
		System.out.println(c.get(Calendar.SECOND));
		
		c.set(Calendar.MONTH,4);
		System.out.println(c.getTime());
		
		Calendar c1 = Calendar.getInstance();
		System.out.println(c.after(c1));
	}

}