feat(SimpleDTO): implement JsonSerializable interface (#795)

Add jsonSerialize method to SimpleDTO class to enable native JSON serialization support via json_encode().
The method utilizes toArray() for data transformation.

Co-authored-by: Deeka Wong <8337659+huangdijia@users.noreply.github.com>

Author: huangdijia

src/SimpleDTO.php

@@ -35,11 +35,12 @@
 use Hyperf\Database\Model\Model;
 use Hyperf\HttpMessage\Upload\UploadedFile;
 use Hyperf\Validation\ValidationException;
+use JsonSerializable;
 use ReflectionClass;
 use ReflectionProperty;
 use UnitEnum;
 
-abstract class SimpleDTO implements BaseDTO, CastsAttributes
+abstract class SimpleDTO implements BaseDTO, CastsAttributes, JsonSerializable
 {
     use DataResolver;
     use DataTransformer;
@@ -142,6 +143,14 @@ public function set($model, $key, $value, $attributes)
         };
     }
 
+    /*
+     * JsonSerializable
+     */
+    public function jsonSerialize(): mixed
+    {
+        return $this->toArray();
+    }
+
     /**
      * Defines the default values for the properties of the DTO.
      */