1 pom依赖

<dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-boot-starter</artifactId><version>3.5.3.1</version>
</dependency>

2 mapper 接口文件

    List<TBookOrder> searchDiy(@Param(Constants.WRAPPER) Wrapper<TBookOrder> queryWrapper);

3 mapper 的xml配置文件

<select id="searchDiy" resultMap="BaseResultMap">selectid, order_id, book_id, user_id, `status`, `count`, bill_time from t_book_order${ew.customSqlSegment}
</select>

4 查询

//无参
QueryWrapper<TBookOrder> queryWrapper_1 = new QueryWrapper<>();
tBookOrderMapper.searchDiy(queryWrapper_1);
System.out.println();
System.out.println();//有参
LambdaQueryWrapper<TBookOrder> queryWrapper = new LambdaQueryWrapper<>();
queryWrapper.eq(TBookOrder::getBookId, 2);
queryWrapper.ge(TBookOrder::getUserId, 1002);
List<TBookOrder> tBookOrders = tBookOrderMapper.searchDiy(queryWrapper);

5 测试，生成的两个sql语句如下

selectid,order_id,book_id,user_id,`status`,`count`,bill_time 
fromt_book_order;selectid,order_id,book_id,user_id,`status`,`count`,bill_time 
fromt_book_order 
WHERE(book_id = 2 AND user_id >= 1002);

注意：不同的版本，可能会有部分区别，总之注意下版本