增加建除十二神；修复由闰月引起的月干支计算错误的问题。

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

@@ -553,7 +553,11 @@ public class Lunar{
    * @return 月天干，如己
    */
   public String getMonthGan(){
-    int m = Math.abs(month)-1;
+    int m = Math.abs(month);
+    int leapMonth = LunarUtil.getLeapMonth(year);
+    if(0==leapMonth||m<leapMonth||month==leapMonth){
+      m-=1;
+    }
     int yearGanIndex = (year-4)%10;
     int offset = (yearGanIndex%5+1)*2;
     return LunarUtil.GAN[(m+offset)%10+1];
@@ -564,7 +568,11 @@ public class Lunar{
    * @return 月地支，如卯
    */
   public String getMonthZhi(){
-    int m = Math.abs(month)-1;
+    int m = Math.abs(month);
+    int leapMonth = LunarUtil.getLeapMonth(year);
+    if(0==leapMonth||m<leapMonth||month==leapMonth){
+      m-=1;
+    }
     return LunarUtil.ZHI[(m+LunarUtil.BASE_MONTH_ZHI_INDEX)%12+1];
   }
 
@@ -871,6 +879,34 @@ public class Lunar{
     return l;
   }
 
+  /**
+   * 获取建除十二神，当月支与日支相同即为建，依次类推
+   * @return 十二神
+   */
+  public String getShiErShen(){
+    String monthZhi = getMonthZhi();
+    String dayZhi = getDayZhi();
+    int indexMonthZhi = 0;
+    int indexDayZhi = 0;
+    for(int i=0,j=LunarUtil.ZHI.length;i<j;i++){
+      String zhi = LunarUtil.ZHI[i];
+      if(zhi.equals(monthZhi)){
+        indexMonthZhi = i;
+      }
+      if(zhi.equals(dayZhi)){
+        indexDayZhi = i;
+      }
+      if(indexMonthZhi>0&&indexDayZhi>0){
+        break;
+      }
+    }
+    int add = indexDayZhi-indexMonthZhi;
+    if(add<0){
+      add = 12+add;
+    }
+    return LunarUtil.SHI_ER_SHEN[1+add];
+  }
+
   public String toFullString(){
     StringBuilder s = new StringBuilder();
     s.append(toString());

src/main/java/com/nlf/calendar/util/LunarUtil.java

@@ -47,6 +47,8 @@ public class LunarUtil{
   public static final String[] POSITION_CAI = {"","艮","艮","坤","坤","坎","坎","震","震","离","离"};
   /** 地支 */
   public static final String[] ZHI = {"","子","丑","寅","卯","辰","巳","午","未","申","酉","戌","亥"};
+  /** 建除十二神 */
+  public static final String[] SHI_ER_SHEN = {"","建","除","满","平","定","执","破","危","成","收","开","闭"};
   /** 彭祖百忌.天干 */
   public static final String[] PENGZU_GAN = {"","甲不开仓财物耗散","乙不栽植千株不长","丙不修灶必见灾殃","丁不剃头头必生疮","戊不受田田主不祥","己不破券二比并亡","庚不经络织机虚张","辛不合酱主人不尝","壬不泱水更难提防","癸不词讼理弱敌强"};
   /** 彭祖百忌.地支 */
@@ -1095,6 +1097,18 @@ public class LunarUtil{
     return diff;
   }
 
+  /**
+   * 获取指定年份的闰月
+   * @param year 年份
+   * @return 闰月数字，1代表闰1月，0代表无闰月
+   */
+  public static int getLeapMonth(int year){
+    int index = year-BASE_YEAR+BASE_INDEX;
+    int v = LUNAR_MONTH[2*index+1];
+    v = (v>>4)&0x0F;
+    return v;
+  }
+
   /**
    * 获取指定年月的下一个月是第几月
    * @param y 农历年