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


public class TestBook {
    
    public static void main(String[] args){
        Date date=new Date();
        Calendar ca=Calendar.getInstance();
        ca.setTime(date);
        SimpleDateFormat format=new SimpleDateFormat("yyyy年MM月dd日");
        String dateString
 
=format.format(date);
        int dayOfYear=ca.get(Calendar.DAY_OF_YEAR);
        int dayOfMonth=ca.get(Calendar.DAY_OF_MONTH);
        int weekOfYear=ca.get(Calendar.WEEK_OF_YEAR);
        System.out.println("當前時間是"+dateString+"--今年的第"+dayOfYear+"天--本月的第"+dayOfMonth+"天");
        System.out.println(
 
"今年的第"+weekOfYear+"周");
    }

}

根據日期推斷某天某周某日