JAVA万年历：农历功能与TXT详解

中国公历算法 http://www.herongyang.com/year_gb/program.html

中国公历算法不是太难，关键是星期值的确定。这里给出了简单算法： 

   public static int dayOfWeek(int y, int m, int d) {
      int w = 1; // 公历一年一月一日是星期一，所以起始值为星期日
      y = (y-1)%400 + 1; // 公历星期值分部 400 年循环一次
      int ly = (y-1)/4; // 闰年次数
      ly = ly - (y-1)/100;
      ly = ly + (y-1)/400;
      int ry = y - 1 - ly; // 常年次数
      w = w + ry; // 常年星期值增一
      w = w + 2*ly; // 闰年星期值增二
      w = w + dayOfYear(y,m,d); 
      w = (w-1)%7 + 1;
      return w;
   }

中国农历算法 

根公历相比，中国农历的算法相当复杂。我在网上找的算法之中，eleworld.com 的算法是最好的一个。这个算法使用了大量的数据来确定农历月份和节气的分部，它仅实用于公历 1901 年到 2100 年之间的 200 年。 

中国农历计算程式 

跟据 eleworld.com 提供的算法，我写了下面这个程式： 

/**
 * ChineseCalendarGB.java
 * Copyright (c) 1997-2002 by Dr. Herong Yang
 * 中国农历算法 - 实用于公历 1901 年至 2100 年之间的 200 年 

 */
import java.text.*;
import java.util.*;
class ChineseCalendarGB {
   private int gregorianYear;
   private int gregorianMonth;
   private int gregorianDate;
   private boolean isGregorianLeap;
   private int dayOfYear;
   private int dayOfWeek; // 周日一星期的第一天
   private int chineseYear;
   private int chineseMonth; // 负数表示闰月
   private int chineseDate;
   private int sectionalTerm;
   private int principleTerm;
   private static char[] daysInGregorianMonth = 
      {31,28,31,30,31,30,31,31,30,31,30,31};
   private static String[] stemNames =
      {"甲","乙","丙","丁","戊","己","庚","辛","壬","癸"};
   private static String[] branchNames =
      {"子","丑","寅","卯","辰","巳","午","未","申","酉","戌","亥"};
   private static String[] animalNames =
      {"鼠","牛","虎","兔","龙","蛇","马","羊","猴","鸡","狗","猪"};
   public static void main(String[] arg) {
      ChineseCalendarGB c = new ChineseCalendarGB();
      String cmd = "day";
      int y = 1901;
      int m = 1;
      int d = 1;
      if (arg.length>0) cmd = arg[0];