添加查询书籍；BookDO映射文件更新；DOMapper添加@Repository注解；添加自定义业务异常处理；添加Validation验证

bookshelfplus/src/main/java/plus/bookshelf/Dao/Mapper/FileObjectDOMapper.java

@@ -1,7 +1,9 @@
 package plus.bookshelf.Dao.Mapper;
 
+import org.springframework.stereotype.Repository;
 import plus.bookshelf.Dao.DO.FileObjectDO;
 
+@Repository
 public interface FileObjectDOMapper {
     /**
      * This method was generated by MyBatis Generator.