Merge pull request 'cjl-dev' (#53) from cjl-dev into master

Reviewed-on: http://120.26.116.243:3000/root/alert-backend/pulls/53

yudao-framework/yudao-common/src/main/java/cn/iocoder/yudao/framework/common/util/json/databind/MultiDateDeserializer.java

@@ -27,6 +27,10 @@ public class MultiDateDeserializer extends JsonDeserializer<Date> {
     public Date deserialize(JsonParser p, DeserializationContext ctxt) throws IOException {
         String text = p.getText().trim();
 
+        if (text.isEmpty()) {
+            return null;
+        }
+
         // ① 如果是纯数字 → 按时间戳处理
         if (text.matches("^\\d+$")) {
             long t = Long.parseLong(text);