refactor code

src/main/java/com/peanut/modules/book/dao/ExpressFeeDao.java

@@ -0,0 +1,10 @@
+package com.peanut.modules.book.dao;
+
+import com.baomidou.mybatisplus.core.mapper.BaseMapper;
+import com.peanut.modules.book.entity.ExpressFee;
+import org.apache.ibatis.annotations.Mapper;
+
+@Mapper
+public interface ExpressFeeDao extends BaseMapper<ExpressFee> {
+
+}