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

public class HelloWorld {

    public static void main(String[] args) {

        //指定時間輸出格式
        SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");

        Date dt = new Date();
        System.out.println("當前時間：" + sdf.format(dt));

        Calendar rightNow = Calendar.getInstance();
        rightNow.setTime(dt);        

        rightNow.add(Calendar.YEAR,-1);//當時日期減1年
        System.out.println("減1年：" + sdf.format(rightNow.getTime()));

        rightNow.add(Calendar.MONTH,3);//(在剛才的結果上)再加3個月
        System.out.println("再加3個月：" + sdf.format(rightNow.getTime()));

        rightNow.add(Calendar.DAY_OF_YEAR,10);//(在剛才的結果上)再加10天        
        System.out.println("再加10天：" + sdf.format(rightNow.getTime()));

 
    }
}