diff --git a/smtweb-system/sw-system-bpm/src/main/java/cc/smtweb/system/bpm/util/CodeGenerator.java b/smtweb-system/sw-system-bpm/src/main/java/cc/smtweb/system/bpm/util/CodeGenerator.java
index f5db28f..0df1a0d 100644
--- a/smtweb-system/sw-system-bpm/src/main/java/cc/smtweb/system/bpm/util/CodeGenerator.java
+++ b/smtweb-system/sw-system-bpm/src/main/java/cc/smtweb/system/bpm/util/CodeGenerator.java
@@ -105,7 +105,7 @@ public class CodeGenerator {
     static class PKGenerator implements TemplateMethodModelEx {
         @Override
         public Object exec(List list) throws TemplateModelException {
-            return DbEngine.getInstance().nextId();
+            return String.valueOf(DbEngine.getInstance().nextId());
 //            return DbEngine.getInstance().nextId();
         }
     }