diff --git a/policeSecurityServer/src/main/java/com/changhu/support/fastjson2/serializer/MinioPrefixSerializer.java b/policeSecurityServer/src/main/java/com/changhu/support/fastjson2/serializer/MinioPrefixSerializer.java
index 5487958..83bc2a5 100644
--- a/policeSecurityServer/src/main/java/com/changhu/support/fastjson2/serializer/MinioPrefixSerializer.java
+++ b/policeSecurityServer/src/main/java/com/changhu/support/fastjson2/serializer/MinioPrefixSerializer.java
@@ -26,5 +26,6 @@ public class MinioPrefixSerializer implements ObjectWriter<String> {
         if (object instanceof String path && StrUtil.isNotEmpty(path)) {
             jsonWriter.writeString(minioPrefix + object);
         }
+        jsonWriter.writeNull();
     }
 }