【fix sonar】CatTreeConverter文件

jero-boot/jero-boot-base/jero-boot-base-generater/src/main/java/com/jero/generater/modules/online/cgform/converter/convertImpl/CatTreeConverter.java

@@ -1,12 +1,14 @@
 
 package com.jero.generater.modules.online.cgform.converter.convertImpl;
 
-import java.util.HashMap;
-import java.util.Map;
 import com.jero.common.util.oConvertUtils;
 import com.jero.generater.modules.online.cgform.converter.convert.ConfigConvert;
 import com.jero.generater.modules.online.cgform.entity.OnlCgformField;
 
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+
 public class CatTreeConverter extends ConfigConvert {
     private String f;
 
@@ -24,11 +26,12 @@ public class CatTreeConverter extends ConfigConvert {
         this.b = var1.getDbFieldName();
     }
 
+    @Override
     public Map<String, String> getConfig() {
         if (oConvertUtils.isEmpty(this.f)) {
-            return null;
+            return Collections.emptyMap();
         } else {
-            HashMap var1 = new HashMap();
+            HashMap<String, String> var1 = new HashMap<>();
             var1.put("treeText", this.f);
             var1.put("field", this.b);
             return var1;