Add add method in DateUtils

src/main/java/run/halo/app/config/properties/HaloProperties.java

@@ -38,6 +38,7 @@ public class HaloProperties {
     private String workDir = HaloConst.USER_HOME + "/.halo/";
 
     public HaloProperties() throws IOException {
+        // Create work directory if not exist
         Files.createDirectories(Paths.get(workDir));
     }
 }

src/main/java/run/halo/app/utils/DateUtils.java

@@ -5,6 +5,7 @@ import org.springframework.util.Assert;
 
 import java.util.Calendar;
 import java.util.Date;
+import java.util.concurrent.TimeUnit;
 
 /**
  * Date utilities.
@@ -41,4 +42,50 @@ public class DateUtils {
         calendar.setTime(date);
         return calendar;
     }
+
+    /**
+     * Adds date.
+     *
+     * @param date     current date must not be null
+     * @param time     time must not be less than 1
+     * @param timeUnit time unit must not be null
+     * @return added date
+     */
+    public static Date add(@NonNull Date date, long time, @NonNull TimeUnit timeUnit) {
+        Assert.notNull(date, "Date must not be null");
+        Assert.isTrue(time >= 0, "Addition time must not be less than 1");
+        Assert.notNull(timeUnit, "Time unit must not be null");
+
+        Date result;
+
+        int timeIntValue;
+
+        if (time > Integer.MAX_VALUE) {
+            timeIntValue = Integer.MAX_VALUE;
+        } else {
+            timeIntValue = Long.valueOf(time).intValue();
+        }
+
+        // Calc the expiry time
+        switch (timeUnit) {
+            case DAYS:
+                result = org.apache.commons.lang3.time.DateUtils.addDays(date, timeIntValue);
+                break;
+            case HOURS:
+                result = org.apache.commons.lang3.time.DateUtils.addHours(date, timeIntValue);
+                break;
+            case MINUTES:
+                result = org.apache.commons.lang3.time.DateUtils.addMinutes(date, timeIntValue);
+                break;
+            case SECONDS:
+                result = org.apache.commons.lang3.time.DateUtils.addSeconds(date, timeIntValue);
+                break;
+            case MILLISECONDS:
+                result = org.apache.commons.lang3.time.DateUtils.addMilliseconds(date, timeIntValue);
+                break;
+            default:
+                result = date;
+        }
+        return result;
+    }
 }