摘自www.mylinux.com.cn
中国公历算法
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?谌?
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：
[HTML]<pre>
/**
* ChineseCalendarGB.java
* Copyright 1997-2002 by Dr. Herong Yang. http://www.herongyang.com/
* 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];
if (arg.length>1) y = Integer.parseInt(arg[1]);
if (arg.length>2) m = Integer.parseInt(arg[2]);
if (arg.length>3) d = Integer.parseInt(arg[3]);
c.setGregorian(y,m,d);
c.computeChineseFields();
c.computeSolarTerms();
if (cmd.equalsIgnoreCase("year")) {
String[] t = c.getYearTable();
for (int i=0; i<t.length; i++) System.out.println(t[i]);
} else if (cmd.equalsIgnoreCase("month")) {
String[] t = c.getMonthTable();
for (int i=0; i<t.length; i++) System.out.println(t[i]);
} else {
System.out.println(c.toString());
}
}
public ChineseCalendarGB() {
setGregorian(1901,1,1);
}
public void setGregorian(int y, int m, int d) {
gregorianYear = y;
gregorianMonth = m;
gregorianDate = d;
isGregorianLeap = isGregorianLeapYear;
dayOfYear = dayOfYear(y,m,d);
dayOfWeek = dayOfWeek(y,m,d);
chineseYear = 0;
chineseMonth = 0;
chineseDate = 0;
sectionalTerm = 0;
principleTerm = 0;
}
public static boolean isGregorianLeapYear(int year) {
boolean isLeap = false;
if (year%4==0) isLeap = true;
if (year%100==0) isLeap = false;
if (year%400==0) isLeap = true;
return isLeap;
}
public static int daysInGregorianMonth(int y, int m) {
int d = daysInGregorianMonth[m-1];
if (m==2 && isGregorianLeapYear) d++; // 公历闰年二月多一天
return d;
}
public static int dayOfYear(int y, int m, int d) {
int c = 0;
for (int i=1; i<m; i++) {
c = c + daysInGregorianMonth(y,i);
}
c = c + d;
return c;
}
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;
}
private static char[] chineseMonths = {
