java学习日历输出

Posted 2020-09-23 从Android出发

import java.text.DateFormatSymbols;
import java.util.Calendar;
import java.util.GregorianCalendar;
import java.util.Locale;

public class Main {

    /**
     * 打印出日历表格
     */
    public static void main(String[] args) {
        
        GregorianCalendar d = new GregorianCalendar();
        int today = d.get(Calendar.DAY_OF_MONTH); //今天是当月的几号
        int month = d.get(Calendar.MONTH); //现在是第几月(因为从0开始算所以得到的月份要加个1)
        d.set(Calendar.DAY_OF_MONTH,1);//将d设置为这个月的第一天
        int weekday = d.get(Calendar.DAY_OF_WEEK);
        
        int firstDayOfWeek = d.getFirstDayOfWeek();
        
        int indent = 0;
        while(weekday != firstDayOfWeek){
            indent++;
            d.add(Calendar.DAY_OF_MONTH,-1);
            weekday = d.get(Calendar.DAY_OF_WEEK);
        }
        
        String[] weekdayNames = new DateFormatSymbols().getShortWeekdays();
        
        do{
            System.out.printf("%4s", weekdayNames[weekday]);
            d.add(Calendar.DAY_OF_MONTH, 1);
            weekday = d.get(Calendar.DAY_OF_WEEK);
            
        }while(weekday != firstDayOfWeek);
        
        System.out.println();
        
        for(int i = 1;i <= indent;i++){
            System.out.print("    ");
        }
        d.set(Calendar.DAY_OF_MONTH, 1);
        
        do{
            int day = d.get(Calendar.DAY_OF_MONTH);
            System.out.printf("%3d",day);
            if(day == today)System.out.print("*");
            else System.out.print(" ");
            d.add(Calendar.DAY_OF_MONTH, 1);
            weekday = d.get(Calendar.DAY_OF_WEEK);
            
            if(weekday == firstDayOfWeek) System.out.println();
        }while(d.get(Calendar.MONTH) == month);
        
        if(weekday != firstDayOfWeek) System.out.println();
    }

}

效果：