Class<?>[] genericTypes = modifier.getGenericReturnTypes();
if (genericTypes.length < 2) {
throw new IllegalArgumentException("please set map generic parameters in method: "
+ modifier.getMethod());
}
KeyColumnOfMap mapKey = modifier.getAnnotation(KeyColumnOfMap.class);
this.keyColumn = (mapKey != null) ? mapKey.value() : null;
this.keyType = genericTypes[0];
this.mapper = mapper;
}