int var(FieldReader fieldReader) {
            return var("_param_" + fieldReader.fieldName, fieldReader.fieldClass);
        }
<blockquote><pre>
     class Bean {
         private String field1;
         private int field2;
     }

     public void readJSONBObject(JSONReader jsonReader, Type fieldType, Object fieldName, long features) {
         features = jsonReader.features(features);
         if (nextIfNull()) {
             return null;
         }

         jsonReader.errorOnNoneSerializable(this.objectClass);

         if (jsonReader.isArray() && jsonReader.isSupportBeanArray()) {
             return readArrayMappingObject(jsonReader, fieldType, fieldName, features);
         }

         Bean object = new Bean();

         jsonReader.nextIfObjectStart();

         for (;;) {
             if (jsonReader.nextIfObjectEnd()) {
                 break;
             }
             switch(jsonReader.getRawInt()) {
                 case field1NameHash32:
                     if(jsonReader.nextIfName4Match2()) {
                         object.field1 = jsonReader.readString();
                         break;
                     }
                     goto hashCode64Start;
                 case field2NameHash32:
                     if(jsonReader.nextIfName4Match2()) {
                         object.field2 = jsonReader.readInt();
                         break;
                     }
                     goto hashCode64Start;
                 default:
                     goto hashCode64Start;
             }

             hashCode64Start:
             long hashCode64 = readFieldNameHashCode();

             if (this.typeKeyHashCode == hashCode64) {
                 object = this.autoType(jsonReader);
             }

             switch(jsonReader.getFieldOrdinal(hashCode64)) {
                 case 0:
                     object.field1 = jsonReader.readString();
             }
         }


     }
 </pre></blockquote>
core/src/main/java/com/alibaba/fastjson2/reader/ObjectReaderCreatorASM.java