阴阳历自动转换工具函数

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

/**
 * @ClassName DateLunarUtil
 * @Author ZhangRF
 * @CreateDate 2020/08/06
 * @Decription 阴阳历自动转换工具函数
 */
public class DateLunarUtil {
    /**
     * 支持转换的最小农历年份
     */
    public static final int MIN_YEAR = 1900;

    /**
     * 支持转换的最大农历年份
     */
    public static final int MAX_YEAR = 2099;

    /**
     * 公历每月前的天数
     */
    private static final int[] DAYS_BEFORE_MONTH = {0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365};
    /**
     * 用来表示1900年到2099年间农历年份的相关信息，共24位bit的16进制表示，其中：
     * 1. 前4位表示该年闰哪个月；
     * 2. 5-17位表示农历年份13个月的大小月分布，0表示小，1表示大；
     * 3. 最后7位表示农历年首（正月初一）对应的公历日期。
     * 以2014年的数据0x955ABF为例说明：
     * 1001 0101 0101 1010 1011 1111
     * 闰九月                                  农历正月初一对应公历1月31号
     */
    private static final int[] LUNAR_INFO = {
            /*1900*/
            0x84B6BF,
            /*1901-1910*/
            0x04AE53, 0x0A5748, 0x5526BD, 0x0D2650, 0x0D9544, 0x46AAB9, 0x056A4D, 0x09AD42, 0x24AEB6, 0x04AE4A,
            /*1911-1920*/
            0x6A4DBE, 0x0A4D52, 0x0D2546, 0x5D52BA, 0x0B544E, 0x0D6A43, 0x296D37, 0x095B4B, 0x749BC1, 0x049754,
            /*1921-1930*/
            0x0A4B48, 0x5B25BC, 0x06A550, 0x06D445, 0x4ADAB8, 0x02B64D, 0x095742, 0x2497B7, 0x04974A, 0x664B3E,
            /*1931-1940*/
            0x0D4A51, 0x0EA546, 0x56D4BA, 0x05AD4E, 0x02B644, 0x393738, 0x092E4B, 0x7C96BF, 0x0C9553, 0x0D4A48,
            /*1941-1950*/
            0x6DA53B, 0x0B554F, 0x056A45, 0x4AADB9, 0x025D4D, 0x092D42, 0x2C95B6, 0x0A954A, 0x7B4ABD, 0x06CA51,
            /*1951-1960*/
            0x0B5546, 0x555ABB, 0x04DA4E, 0x0A5B43, 0x352BB8, 0x052B4C, 0x8A953F, 0x0E9552, 0x06AA48, 0x6AD53C,
            /*1961-1970*/
            0x0AB54F, 0x04B645, 0x4A5739, 0x0A574D, 0x052642, 0x3E9335, 0x0D9549, 0x75AABE, 0x056A51, 0x096D46,
            /*1971-1980*/
            0x54AEBB, 0x04AD4F, 0x0A4D43, 0x4D26B7, 0x0D254B, 0x8D52BF, 0x0B5452, 0x0B6A47, 0x696D3C, 0x095B50,
            /*1981-1990*/
            0x049B45, 0x4A4BB9, 0x0A4B4D, 0xAB25C2, 0x06A554, 0x06D449, 0x6ADA3D, 0x0AB651, 0x095746, 0x5497BB,
            /*1991-2000*/
            0x04974F, 0x064B44, 0x36A537, 0x0EA54A, 0x86B2BF, 0x05AC53, 0x0AB647, 0x5936BC, 0x092E50, 0x0C9645,
            /*2001-2010*/
            0x4D4AB8, 0x0D4A4C, 0x0DA541, 0x25AAB6, 0x056A49, 0x7AADBD, 0x025D52, 0x092D47, 0x5C95BA, 0x0A954E,
            /*2011-2020*/
            0x0B4A43, 0x4B5537, 0x0AD54A, 0x955ABF, 0x04BA53, 0x0A5B48, 0x652BBC, 0x052B50, 0x0A9345, 0x474AB9,
            /*2021-2030*/
            0x06AA4C, 0x0AD541, 0x24DAB6, 0x04B64A, 0x6a573D, 0x0A4E51, 0x0D2646, 0x5E933A, 0x0D534D, 0x05AA43,
            /*2031-2040*/
            0x36B537, 0x096D4B, 0xB4AEBF, 0x04AD53, 0x0A4D48, 0x6D25BC, 0x0D254F, 0x0D5244, 0x5DAA38, 0x0B5A4C,
            /*2041-2050*/
            0x056D41, 0x24ADB6, 0x049B4A, 0x7A4BBE, 0x0A4B51, 0x0AA546, 0x5B52BA, 0x06D24E, 0x0ADA42, 0x355B37,
            /*2051-2060*/
            0x09374B, 0x8497C1, 0x049753, 0x064B48, 0x66A53C, 0x0EA54F, 0x06AA44, 0x4AB638, 0x0AAE4C, 0x092E42,
            /*2061-2070*/
            0x3C9735, 0x0C9649, 0x7D4ABD, 0x0D4A51, 0x0DA545, 0x55AABA, 0x056A4E, 0x0A6D43, 0x452EB7, 0x052D4B,
            /*2071-2080*/
            0x8A95BF, 0x0A9553, 0x0B4A47, 0x6B553B, 0x0AD54F, 0x055A45, 0x4A5D38, 0x0A5B4C, 0x052B42, 0x3A93B6,
            /*2081-2090*/
            0x069349, 0x7729BD, 0x06AA51, 0x0AD546, 0x54DABA, 0x04B64E, 0x0A5743, 0x452738, 0x0D264A, 0x8E933E,
            /*2091-2099*/
            0x0D5252, 0x0DAA47, 0x66B53B, 0x056D4F, 0x04AE45, 0x4A4EB9, 0x0A4D4C, 0x0D1541, 0x2D92B5
    };

    /**
     * 将农历日期转换为公历日期
     *
     * @param date 农历日期
     * @return 返回农历日期对应的公历日期，year0, month1, day2.
     */
    public static final String lunarToSolar(String date) {
        int year = Integer.parseInt(date.substring(0, 4));
        int month = Integer.parseInt(date.substring(5, 7));
        int monthDay = Integer.parseInt(date.substring(8, 10));
        int dayOffset;
        boolean isLeapMonth = false;
        //校验是不是润月
        if (leapMonth(year) == month) {
            isLeapMonth = true;
        }
        int leapMonth;

        int i;
        int iMonth = 0;
        int iDay = 0;


        if (year < MIN_YEAR || year > MAX_YEAR || month < 1 || month > 12
                || monthDay < 1 || monthDay > 30) {
            throw new IllegalArgumentException(
                    "Illegal lunar date, must be like that:\n\t" +
                            "year : 1900~2099\n\t" +
                            "month : 1~12\n\t" +
                            "day : 1~30");
        }
        dayOffset = (LUNAR_INFO[year - MIN_YEAR] & 0x001F) - 1;
        if (((LUNAR_INFO[year - MIN_YEAR] & 0x0060) >> 5) == 2) {
            dayOffset += 31;
        }
        for (i = 1; i < month; i++) {
            if ((LUNAR_INFO[year - MIN_YEAR] & (0x80000 >> (i - 1))) == 0) {
                dayOffset += 29;
            } else {
                dayOffset += 30;
            }
        }
        dayOffset += monthDay;

        leapMonth = (LUNAR_INFO[year - MIN_YEAR] & 0xf00000) >> 20;

        // 这一年有闰月

        if (leapMonth != 0) {
            if (month > leapMonth || (month == leapMonth && isLeapMonth)) {

                if ((LUNAR_INFO[year - MIN_YEAR] & (0x80000 >> (month - 1))) == 0) {
                    dayOffset += 29;
                } else {
                    dayOffset += 30;
                }
            }
        }

        if (dayOffset > 366 || (year % 4 != 0 && dayOffset > 365)) {
            year += 1;

            if (year % 4 == 1) {
                dayOffset -= 366;
            } else {
                dayOffset -= 365;
            }
        }

        for (i = 1; i < 13; i++) {
            int iPos = DAYS_BEFORE_MONTH[i];

            if (year % 4 == 0 && i > 2) {

                iPos += 1;
            }

            if (year % 4 == 0 && i == 2 && iPos + 1 == dayOffset) {

                iMonth = i;

                iDay = dayOffset - 31;

                break;

            }
            if (iPos >= dayOffset) {
                iMonth = i;
                iPos = DAYS_BEFORE_MONTH[i - 1];
                if (year % 4 == 0 && i > 2) {
                    iPos += 1;
                }
                if (dayOffset > iPos) {
                    iDay = dayOffset - iPos;
                } else if (dayOffset == iPos) {
                    if (year % 4 == 0 && i == 2) {
                        iDay = DAYS_BEFORE_MONTH[i] - DAYS_BEFORE_MONTH[i - 1] + 1;
                    } else {
                        iDay = DAYS_BEFORE_MONTH[i] - DAYS_BEFORE_MONTH[i - 1];
                    }
                } else {
                    iDay = dayOffset;
                }
                break;
            }
        }
        String iMonths = "";
        String iDays = "";
        if (iMonth < 10) {
            iMonths = "0" + iMonth;
        } else {
            iMonths = String.valueOf(iMonth);
        }
        if (iDay < 10) {
            iDays = "0" + iDay;
        } else {
            iDays = String.valueOf(iDay);
        }
        return year + "-" + iMonths + "-" + iDays;
    }

    /**
     * 将公历日期转换为农历日期，且标识是否是闰月
     *
     * @param format
     * @return 返回公历日期对应的农历日期，year0，month1，day2，leap3
     */
    public static final String solarToLunar(String format) {
//        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        try {
//            String format = sdf.format(date);
            int year = Integer.valueOf(format.substring(0, 4));
            int month = Integer.valueOf(format.substring(5, 7));
            int monthDay = Integer.valueOf(format.substring(8, 10));
            String lunarDate = "";
            Date baseDate = new GregorianCalendar(1900, 0, 31).getTime();
            Date objDate = new GregorianCalendar(year, month - 1, monthDay).getTime();
            int offset = (int) ((objDate.getTime() - baseDate.getTime()) / 86400000L);
            // 用offset减去每农历年的天数计算当天是农历第几天
            // iYear最终结果是农历的年份, offset是当年的第几天
            int iYear, daysOfYear = 0;
            for (iYear = MIN_YEAR; iYear <= MAX_YEAR && offset > 0; iYear++) {
                daysOfYear = daysInLunarYear(iYear);
                offset -= daysOfYear;
            }
            if (offset < 0) {
                offset += daysOfYear;
                iYear--;
            }
            // 农历年份
            lunarDate = String.valueOf(iYear);
            int leapMonth = leapMonth(iYear);
            // 闰哪个月,1-12
            boolean isLeap = false;
            // 用当年的天数offset,逐个减去每月（农历）的天数，求出当天是本月的第几天
            int iMonth, daysOfMonth = 0;
            for (iMonth = 1; iMonth <= 13 && offset > 0; iMonth++) {
                daysOfMonth = daysInLunarMonth(iYear, iMonth);
                offset -= daysOfMonth;
            }
            // 当前月超过闰月，要校正
            if (leapMonth != 0 && iMonth > leapMonth) {
                --iMonth;
                if (iMonth == leapMonth) {
                    isLeap = true;
                }
            }
            // offset小于0时，也要校正
            if (offset < 0) {
                offset += daysOfMonth;
                --iMonth;
            }
            String iMonths = "";
            String iDays = "";
            if (iMonth < 10) {
                iMonths = "0" + iMonth;
            } else {
                iMonths = String.valueOf(iMonth);
            }
            int iDay = offset + 1;
            if (iDay < 10) {
                iDays = "0" + iDay;
            } else {
                iDays = String.valueOf(iDay);
            }
            lunarDate = lunarDate + "-" + iMonths + "-" + iDays;
//            lunarDate[3] = isLeap ? 1 : 0;
            return lunarDate;
        } catch (Exception e) {
        }
        return null;
    }

    public static final String solarToLunar(Date date) {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        String format = sdf.format(date);
        return solarToLunar(format);
    }

    /**
     * 传回农历year年month月的总天数
     *
     * @param year  要计算的年份
     * @param month 要计算的月
     * @return 传回天数
     */
    final public static int daysInMonth(int year, int month) {
        return daysInMonth(year, month, false);
    }

    /**
     * 传回农历year年month月的总天数
     *
     * @param year  要计算的年份
     * @param month 要计算的月
     * @param leap  当月是否是闰月
     * @return 传回天数，如果闰月是错误的，返回0.
     */
    public static final int daysInMonth(int year, int month, boolean leap) {
        int leapMonth = leapMonth(year);
        int offset = 0;
        // 如果本年有闰月且month大于闰月时，需要校正
        if (leapMonth != 0 && month > leapMonth) {
            offset = 1;
        }
        // 不考虑闰月
        if (!leap) {
            return daysInLunarMonth(year, month + offset);
        } else {
            // 传入的闰月是正确的月份
            if (leapMonth != 0 && leapMonth == month) {
                return daysInLunarMonth(year, month + 1);
            }
        }
        return 0;
    }

    /**
     * 传回农历 year年的总天数
     *
     * @param year 将要计算的年份
     * @return 返回传入年份的总天数
     */
    private static int daysInLunarYear(int year) {
        int i, sum = 348;
        if (leapMonth(year) != 0) {
            sum = 377;
        }
        int monthInfo = LUNAR_INFO[year - MIN_YEAR] & 0x0FFF80;
        for (i = 0x80000; i > 0x7; i >>= 1) {
            if ((monthInfo & i) != 0) {
                sum += 1;
            }
        }
        return sum;
    }

    /**
     * 传回农历 year年month月的总天数，总共有13个月包括闰月
     *
     * @param year  将要计算的年份
     * @param month 将要计算的月份
     * @return 传回农历 year年month月的总天数
     */
    private static int daysInLunarMonth(int year, int month) {
        if ((LUNAR_INFO[year - MIN_YEAR] & (0x100000 >> month)) == 0) {
            return 29;
        } else {
            return 30;
        }
    }

    /**
     * 传回农历 year年闰哪个月 1-12 , 没闰传回 0
     *
     * @param year 将要计算的年份
     * @return 传回农历 year年闰哪个月1-12, 没闰传回 0
     */
    private static int leapMonth(int year) {
        return ((LUNAR_INFO[year - MIN_YEAR] & 0xF00000)) >> 20;
    }

    public static void main(String[] args) {
        System.out.println(solarToLunar(new Date()));
        System.out.println(lunarToSolar("2020-07-23"));
    }