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：
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/**
* ChineseCalendarGB.java
* Copyright (c) 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
} else if (cmd.equalsIgnoreCase("month")) {
String[] t = c.getMonthTable();
for (int i=0; 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(y);
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(y)) 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
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 = {
// 农历月份大小压缩表，两个字节表示一年。两个字节共十六个二进制位数，
// 前四个位数表示闰月月份，后十二个位数表示十二个农历月份的大小。
0x00,0x04,0xad,0x08,0x5a,0x01,0xd5,0x54,0xb4,0x09,0x64,0x05,0x59,0x45,
0x95,0x0a,0xa6,0x04,0x55,0x24,0xad,0x08,0x5a,0x62,0xda,0x04,0xb4,0x05,
0xb4,0x55,0x52,0x0d,0x94,0x0a,0x4a,0x2a,0x56,0x02,0x6d,0x71,0x6d,0x01,
0xda,0x02,0xd2,0x52,0xa9,0x05,0x49,0x0d,0x2a,0x45,0x2b,0x09,0x56,0x01,
0xb5,0x20,0x6d,0x01,0x59,0x69,0xd4,0x0a,0xa8,0x05,0xa9,0x56,0xa5,0x04,
0x2b,0x09,0x9e,0x38,0xb6,0x08,0xec,0x74,0x6c,0x05,0xd4,0x0a,0xe4,0x6a,
0x52,0x05,0x95,0x0a,0x5a,0x42,0x5b,0x04,0xb6,0x04,0xb4,0x22,0x6a,0x05,
0x52,0x75,0xc9,0x0a,0x52,0x05,0x35,0x55,0x4d,0x0a,0x5a,0x02,0x5d,0x31,
0xb5,0x02,0x6a,0x8a,0x68,0x05,0xa9,0x0a,0x8a,0x6a,0x2a,0x05,0x2d,0x09,
0xaa,0x48,0x5a,0x01,0xb5,0x09,0xb0,0x39,0x64,0x05,0x25,0x75,0x95,0x0a,
0x96,0x04,0x4d,0x54,0xad,0x04,0xda,0x04,0xd4,0x44,0xb4,0x05,0x54,0x85,
0x52,0x0d,0x92,0x0a,0x56,0x6a,0x56,0x02,0x6d,0x02,0x6a,0x41,0xda,0x02,
0xb2,0xa1,0xa9,0x05,0x49,0x0d,0x0a,0x6d,0x2a,0x09,0x56,0x01,0xad,0x50,
0x6d,0x01,0xd9,0x02,0xd1,0x3a,0xa8,0x05,0x29,0x85,0xa5,0x0c,0x2a,0x09,
0x96,0x54,0xb6,0x08,0x6c,0x09,0x64,0x45,0xd4,0x0a,0xa4,0x05,0x51,0x25,
0x95,0x0a,0x2a,0x72,0x5b,0x04,0xb6,0x04,0xac,0x52,0x6a,0x05,0xd2,0x0a,
0xa2,0x4a,0x4a,0x05,0x55,0x94,0x2d,0x0a,0x5a,0x02,0x75,0x61,0xb5,0x02,
0x6a,0x03,0x61,0x45,0xa9,0x0a,0x4a,0x05,0x25,0x25,0x2d,0x09,0x9a,0x68,
0xda,0x08,0xb4,0x09,0xa8,0x59,0x54,0x03,0xa5,0x0a,0x91,0x3a,0x96,0x04,
0xad,0xb0,0xad,0x04,0xda,0x04,0xf4,0x62,0xb4,0x05,0x54,0x0b,0x44,0x5d,
0x52,0x0a,0x95,0x04,0x55,0x22,0x6d,0x02,0x5a,0x71,0xda,0x02,0xaa,0x05,
0xb2,0x55,0x49,0x0b,0x4a,0x0a,0x2d,0x39,0x36,0x01,0x6d,0x80,0x6d,0x01,
0xd9,0x02,0xe9,0x6a,0xa8,0x05,0x29,0x0b,0x9a,0x4c,0xaa,0x08,0xb6,0x08,
0xb4,0x38,0x6c,0x09,0x54,0x75,0xd4,0x0a,0xa4,0x05,0x45,0x55,0x95,0x0a,
0x9a,0x04,0x55,0x44,0xb5,0x04,0x6a,0x82,0x6a,0x05,0xd2,0x0a,0x92,0x6a,
0x4a,0x05,0x55,0x0a,0x2a,0x4a,0x5a,0x02,0xb5,0x02,0xb2,0x31,0x69,0x03,
0x31,0x73,0xa9,0x0a,0x4a,0x05,0x2d,0x55,0x2d,0x09,0x5a,0x01,0xd5,0x48,
0xb4,0x09,0x68,0x89,0x54,0x0b,0xa4,0x0a,0xa5,0x6a,0x95,0x04,0xad,0x08,
0x6a,0x44,0xda,0x04,0x74,0x05,0xb0,0x25,0x54,0x03
};
// 初始日，公历农历对应日期：
// 公历 1901 年 1 月 1 日，对应农历 4598 年 11 月 11 日
private static int baseYear = 1901;
private static int baseMonth = 1;
private static int baseDate = 1;
private static int baseIndex = 0;
private static int baseChineseYear = 4598-1;
private static int baseChineseMonth = 11;
private static int baseChineseDate = 11;
public int computeChineseFields() {
if (gregorianYear<1901 || gregorianYear>2100) return 1;
int startYear = baseYear;
int startMonth = baseMonth;
int startDate = baseDate;
chineseYear = baseChineseYear;
chineseMonth = baseChineseMonth;
chineseDate = baseChineseDate;
// 第二个对应日，用以提高计算效率
// 公历 2000 年 1 月 1 日，对应农历 4697 年 11 月 25 日
if (gregorianYear >= 2000) {
startYear = baseYear + 99;
startMonth = 1;
startDate = 1;
chineseYear = baseChineseYear + 99;
chineseMonth = 11;
chineseDate = 25;
}
int daysDiff = 0;
for (int i=startYear; i
daysDiff += 365;
if (isGregorianLeapYear(i)) daysDiff += 1; // leap year
}
for (int i=startMonth; i
daysDiff += daysInGregorianMonth(gregorianYear,i);
}
daysDiff += gregorianDate - startDate;
chineseDate += daysDiff;
int lastDate = daysInChineseMonth(chineseYear, chineseMonth);
int nextMonth = nextChineseMonth(chineseYear, chineseMonth);
while (chineseDate>lastDate) {
if (Math.abs(nextMonth)
chineseMonth = nextMonth;
chineseDate -= lastDate;
lastDate = daysInChineseMonth(chineseYear, chineseMonth);
nextMonth = nextChineseMonth(chineseYear, chineseMonth);
}
return 0;
}
private static int[] bigLeapMonthYears = {
// 大闰月的闰年年份
6, 14, 19, 25, 33, 36, 38, 41, 44, 52,
55, 79,117,136,147,150,155,158,185,193
};
public static int daysInChineseMonth(int y, int m) {
