优化儒略日计算；使用最新寿星天文历算法修复节气误差。

src/main/java/com/nlf/calendar/Solar.java

@@ -105,55 +105,46 @@ public class Solar{
    * @param julianDay 儒略日
    */
   public Solar(double julianDay){
-    julianDay += 0.5;
+    int d = (int)(julianDay + 0.5);
+    double f = julianDay + 0.5 - d;
+    int c;
 
-    // 日数的整数部份
-    double a = int2(julianDay);
-    // 日数的小数部分
-    double f = julianDay - a;
-    double jd;
-
-    if (a > 2299161) {
-      jd = int2((a - 1867216.25) / 36524.25);
-      a += 1 + jd - int2(jd / 4);
+    if (d >= 2299161) {
+      c = (int)((d - 1867216.25) / 36524.25);
+      d += 1 + c - (int)(c * 1D / 4);
     }
-    // 向前移4年零2个月
-    a += 1524;
-    double y = int2((a - 122.1) / 365.25);
-    // 去除整年日数后余下日数
-    jd = a - int2(365.25 * y);
-    double m = (int)int2(jd / 30.6001);
-    // 去除整月日数后余下日数
-    double d = (int)int2(jd - int2(m * 30.6001));
-    y -= 4716;
-    m--;
-    if (m > 12) {
-      m -= 12;
+    d += 1524;
+    int year = (int)((d - 122.1) / 365.25);
+    d -= (int)(365.25 * year);
+    int month = (int)(d * 1D / 30.601);
+    d -= (int)(30.601 * month);
+    int day = d;
+    if (month > 13) {
+      month -= 13;
+      year -= 4715;
+    } else {
+      month -= 1;
+      year -= 4716;
     }
-    if (m <= 2) {
-      y++;
-    }
-
-    // 日的小数转为时分秒
     f *= 24;
-    double h = (int)int2(f);
+    int hour = (int)f;
 
-    f -= h;
+    f -= hour;
     f *= 60;
-    double mi = int2(f);
+    int minute = (int)f;
 
-    f -= mi;
+    f -= minute;
     f *= 60;
-    double s = int2(f);
+    int second = (int)Math.round(f);
 
     calendar = Calendar.getInstance();
-    calendar.set((int)y,(int)m-1,(int)d,(int)h,(int)mi,(int)s);
-    year = calendar.get(Calendar.YEAR);
-    month = calendar.get(Calendar.MONTH)+1;
-    day = calendar.get(Calendar.DATE);
-    hour = calendar.get(Calendar.HOUR_OF_DAY);
-    minute = calendar.get(Calendar.MINUTE);
-    second = calendar.get(Calendar.SECOND);
+    calendar.set(year,month-1,day,hour,minute,second);
+    this.year = year;
+    this.month = month;
+    this.day = day;
+    this.hour = hour;
+    this.minute = minute;
+    this.second = second;
   }
 
   /**
@@ -388,38 +379,28 @@ public class Solar{
     return new Lunar(calendar.getTime());
   }
 
-  private double int2(double v){
-    v = Math.floor(v);
-    return v<0?v+1:v;
-  }
-
   /**
    * 获取儒略日
    * @return 儒略日
    */
   public double getJulianDay(){
-    double y = this.year;
-    double m = this.month;
-    double n = 0;
-
+    int y = this.year;
+    int m = this.month;
+    double d = this.day + ((this.second *1D / 60 + this.minute) / 60 + this.hour) / 24;
+    int n = 0;
+    boolean g = false;
+    if (y * 372 + m * 31 + (int)d >= 588829) {
+      g = true;
+    }
     if (m <= 2) {
       m += 12;
       y--;
     }
-
-    // 判断是否为UTC日1582*372+10*31+15
-    if (this.year * 372 + this.month * 31 + this.day >= 588829) {
-      n = int2(y / 100);
-      // 加百年闰
-      n = 2 - n + int2(n / 4);
+    if (g) {
+      n = (int)(y * 1D / 100);
+      n = 2 - n + (int)(n * 1D / 4);
     }
-
-    // 加上年引起的偏移日数
-    n += int2(365.2500001 * (y + 4716));
-    // 加上月引起的偏移日数及日偏移数
-    n += int2(30.6 * (m + 1)) + this.day;
-    n += ((this.second *1D / 60 + this.minute) / 60 + this.hour) / 24 - 1524.5;
-    return n;
+    return (int)(365.25 * (y + 4716)) + (int)(30.6001 * (m + 1)) + d + n - 1524.5;
   }
 
   /**