新增日期叠加工具方法

framework-base/src/main/java/com/chelvc/framework/base/util/DateUtils.java

@@ -1209,4 +1209,27 @@ public final class DateUtils {
         Calendar calendar = Calendar.getInstance();
         return calendar.get(field);
     }
+
+    /**
+     * 叠加日期
+     *
+     * @param date  日期对象
+     * @param other 日期对象
+     * @return 日期对象
+     */
+    public static Date superpose(Date date, Date other) {
+        if (date == null) {
+            return other;
+        } else if (other == null) {
+            return date;
+        }
+
+        long t1 = date.getTime(), t2 = other.getTime(), now = System.currentTimeMillis();
+        if (t1 <= now && t2 <= now) {
+            return t1 < t2 ? other : date;
+        } else if (t1 > now && t2 > now) {
+            return new Date(t1 + t2 - now);
+        }
+        return t1 > now ? date : other;
+    }
 }