增加年龄计算

@@ -31,6 +31,8 @@ public final class DateUtil {
 
     public static String F8 = "yyyyMMdd";
 
+    public static String F6 = "yyyyMM";
+
     public static String[] dataStringFormats = {F8, F10, F14, F19, "yyyy/MM/dd", "yyyy/MM/dd HH:mm", "yyyy/MM/dd HH:mm:ss", "yyyy-MM-dd HH:mm"};
 
     private static Date currentDate = new Date();
@@ -445,4 +447,41 @@ public final class DateUtil {
         Instant instant = localDateTime.atZone(zone).toInstant();
         java.util.Date date = Date.from(instant);
     }
+
+    /**
+     * 根据出生日期计算年龄
+     * @param birthDay
+     * @return
+     * @throws ParseException
+     */
+    public static int getAgeByBirth(Date birthDay) throws ParseException {
+        int age = 0;
+        Calendar cal = Calendar.getInstance();
+        //出生日期晚于当前时间，无法计算
+        if (cal.before(birthDay)) {
+            throw new IllegalArgumentException(
+                    "The birthDay is before Now.It's unbelievable!");
+        }
+        //当前年份
+        int yearNow = cal.get(Calendar.YEAR);
+        //当前月份
+        int monthNow = cal.get(Calendar.MONTH);
+        //当前日期
+        int dayOfMonthNow = cal.get(Calendar.DAY_OF_MONTH);
+        cal.setTime(birthDay);
+        int yearBirth = cal.get(Calendar.YEAR);
+        int monthBirth = cal.get(Calendar.MONTH);
+        int dayOfMonthBirth = cal.get(Calendar.DAY_OF_MONTH);
+        //计算整岁数
+        age = yearNow - yearBirth;
+        if (monthNow <= monthBirth) {
+            if (monthNow == monthBirth) {
+                //当前日期在生日之前，年龄减一
+                if (dayOfMonthNow < dayOfMonthBirth){ age--;}
+            } else {
+                age--;//当前月份在生日之前，年龄减一
+            }
+        }
+        return age;
+    }
 }