常用類之日期(Date Calendar)
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
public class DateAndCalendarTest
{
public static void main(String[] args)
{
//Date類對象表示當前日期和時間
//劃橫線的爲過時的方法 就是java不建議再使用的
Date nowDate=new Date();
System.out.println("當前年:"+(nowDate.getYear()+1900));
System.out.println("當前月:"+(nowDate.getMonth()+1));
System.out.println("當前日:"+nowDate.getDate());
System.out.println("當前星期:"+nowDate.getDay());
System.out.println("當前時:"+nowDate.getHours());
System.out.println("當前分:"+nowDate.getMinutes());
System.out.println("當前秒:"+nowDate.getSeconds());
System.out.println("從1970年1月1日起到現在的毫秒:"+nowDate.getTime());
System.out.println("現在的時間是:"+nowDate.toString());
System.out.println("現在的時間是(本地格式):"+nowDate.toLocaleString());
System.out.println("現在的時間是(格林威治時間格式):"+nowDate.toGMTString());
System.out.println("================================");
//常用的時間格式 和 對應方法
//其中yyyy-MM-dd是你要表示的格式
SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String systemtime=sdf.format(nowDate);
System.out.println(systemtime);
sdf=new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
systemtime=sdf.format(nowDate);
System.out.println(systemtime);
System.out.println("================================");
//時間性能測試,測試代碼運行的時間
long startTime=new Date().getTime();
//這裏是你自己的方法
long endTime=new Date().getTime();
System.out.println("程序執行用時:"+(endTime-startTime)+"毫秒");
System.out.println("================================");
System.out.println("當前年:"+Calendar.getInstance().get(Calendar.YEAR)); //返回默認地區和時區的Calendar對象
System.out.println("當前月:"+Calendar.getInstance().get(Calendar.MONTH)+1);
System.out.println("當前日(月中的):"+Calendar.getInstance().get(Calendar.DAY_OF_MONTH));
System.out.println("當前日(年中的):"+Calendar.getInstance().get(Calendar.DAY_OF_YEAR));
System.out.println("當前星期:"+Calendar.getInstance().get(Calendar.DAY_OF_WEEK)); //週日是第一天
System.out.println("當前時:"+Calendar.getInstance().get(Calendar.HOUR_OF_DAY));
System.out.println("當前分:"+Calendar.getInstance().get(Calendar.MINUTE));
System.out.println("當前秒:"+Calendar.getInstance().get(Calendar.SECOND));
System.out.println("================================");
Calendar muBirthday = Calendar.getInstance();
muBirthday.set(Calendar.YEAR, 1986);
muBirthday.set(Calendar.MONTH, 3);
muBirthday.set(Calendar.DAY_OF_MONTH,19);
System.out.println("我的生日是在一年中的第:"+muBirthday.get(Calendar.DAY_OF_YEAR)+"天");
System.out.println("我的生日是:"+(new Date(muBirthday.getTimeInMillis())).toLocaleString());
System.out.println("================================");
Calendar calObj = Calendar.getInstance();
calObj.add(Calendar.YEAR, 1);
System.out.println("1年後:"+calObj.getTime().toLocaleString());
}
}