在Mybatis @Select注解中实现拼写动态sql
现在随着mybatis plus的应用,越来越多的弱化了sql语句,对于单表操作可以说几乎不需要进行自己编写sql语句了,但对于多表查询操作目前mybatis plus还没有很好的支持,还需要自己编写sql语句,如:
import java.util.list; import org.apache.ibatis.annotations.mapper; import org.apache.ibatis.annotations.param; import org.apache.ibatis.annotations.select; import com.baomidou.mybatisplus.mapper.basemapper; import com.shield.base.model.domain.menudo; import com.shield.base.model.param.menutreeparam; /** * 基础数据操作对象 * * @author xxx * @date 2018/5/18 */ @mapper public interface menudao extends basemapper<menudo> { /** * 根据菜单编码获得所有下级菜单列表(包括本级) * @param menuid 菜单编码 * @return 该菜单下的所有菜单列表(包括本级) */ @select("with menutree" + " as" + "(" + " select menu1.father_rowid as id,menu1.son_rowid as parentid,menu1.system_name as menuname," + "menu1.system_full_rowid as menutreeflat,menu1.level_value as menulevel,menu1.homepage_status as homestatus," + "menu1.menu_status as menutype,menu1.sort as sort,menu1.duty_name as createname," + "menu1.duty_datetime as createdate,menu1.update_datetime as updatedate,menu1.stop_status as status" + " from system_menu_setup menu1 where menu1.father_rowid = #{menuid}" + " union all" + " select menu2.father_rowid as id,menu2.son_rowid as parentid,menu2.system_name as menuname," + "menu2.system_full_rowid as menutreeflat,menu2.level_value as menulevel,menu2.homepage_status as homestatus," + "menu2.menu_status as menutype,menu2.sort as sort,menu2.duty_name as createname," + "menu2.duty_datetime as createdate,menu2.update_datetime as updatedate,menu2.stop_status as status" + " from system_menu_setup menu2" + " inner join menutree t on menu2.son_rowid = t.id" + ")" + " select id,parentid,menuname,menutreeflat,menulevel,homestatus,menutype,sort,createname," + "createdate,updatedate,status from menutree") list<menudo> selectmenutreelist(@param(value = "menuid") long menuid); }
这样整个语句基本上都是写死的,没有办法通过参数动态拼接sql语句,在对于 相同语句不同参数来拼接sql语句是十分不便的,而如果使用xml来配置的话可以用
<where> <if test="stopstatus != null"> and menu.stop_status=#{stopstatus} and rolemenu.stop_status=#{stopstatus} </if> <if test="menusource != null"> and menusource.menu_source=#{menusource} </if> <if test="userid != null"> and roleuser.operator_rowid=#{userid} </if> </where>
但是现在很多公司可能会采用@select注解方式来编写sql语句,而非通过xml 的sql mapper,那对于@select这种该如何做呢?其实很简单,只是需要用<script>标签包围,然后像xml语法一样书写即可,无须任何其他类或自定义注解类来完成,具体事例如下:
package com.szss.shield.base.dao; import java.util.list; import org.apache.ibatis.annotations.mapper; import org.apache.ibatis.annotations.param; import org.apache.ibatis.annotations.select; import com.baomidou.mybatisplus.mapper.basemapper; import com.shield.base.model.domain.menudo; import com.shield.base.model.param.menutreeparam; /** * 基础数据操作对象 * * @author xxxx * @date 2018/5/18 */ @mapper public interface menudao extends basemapper<menudo> { /** * 根据当前用户权限获取所有权限内的菜单列表(不分页) * @param menutreeparam 菜单参数 * @return 当前用户权限获取所有权限内的菜单列表 */ @select("<script>" + " with menutree" + " as" + " (" + " select menu.father_rowid as id,menu.son_rowid as parentid,menu.system_name as menuname,\n" + " menu.level_value as menulevel,menu.homepage_status as homestatus,\n" + " menu.menu_status as menutype,menu.sort as sort,menu.stop_status as status,cast(max(menusource.menu_path_url) as varchar) as menuurl \n" + "from system_menu_setup menu \n" + " left join system_menu_source_setup menusource\n" + " on menu.father_rowid=menusource.system_menu_rowid \n" + " left join system_role_custom_menu_setup rolemenu \n" + " on menu.father_rowid=rolemenu.system_menu_rowid \n" + " left join system_role_operator_setup roleuser \n" + " on roleuser.system_role_setup_rowid=rolemenu.system_role_rowid \n" + " left join system_role_setup role \n" + " on roleuser.system_role_setup_rowid=role.rowid\n" + " left join system_department_menu_setup depmenu\n" + " on menu.father_rowid=depmenu.system_menu_rowid\n" + "<where>" + "<if test='stopstatus != null'>" + " and menu.stop_status=#{stopstatus} and rolemenu.stop_status=#{stopstatus}\n" +"</if>" + "<if test='menusource != null'>" + " and menusource.menu_source=#{menusource}" +"</if>" + "<if test='userid != null'>" + " and roleuser.operator_rowid=#{userid}\n" +"</if>" +"</where>" + " group by menu.father_rowid ,menu.son_rowid ,menu.system_name,menu.level_value,menu.homepage_status,\n" + " menu.menu_status,menu.sort,menu.duty_name,menu.duty_datetime,menu.update_datetime,menu.stop_status\n" + " union all\n" + " select menu2.father_rowid as id,menu2.son_rowid as parentid,menu2.system_name as menuname,\n" + " menu2.level_value as menulevel,menu2.homepage_status as homestatus,\n" + " menu2.menu_status as menutype,menu2.sort as sort,menu2.stop_status as status,cast('' as varchar) as menuurl\n" + " from system_menu_setup menu2\n" + " inner join menutree t on menu2.father_rowid= t.parentid\n" + " )\n" + " select id,parentid,menuname,menulevel,homestatus,menutype,sort,status,max(menuurl) as menuurl from menutree\n" + " group by id,parentid,menuname,menulevel,homestatus,menutype,sort,status\n" + " order by menulevel,sort" + " </script>") list<menudo> selectmenutreelistbyuserid(menutreeparam menutreeparam); }
至此我们就可以像在xml文件里面一样愉快的动态拼接你想要的sql语句了!
注意:
在@select注解中采用<script>标签包围拼接sql语句时不能在标签里有>大于或<小于符号出现,否则会报caused by: org.xml.sax.saxparseexception: 元素内容必须由格式正确的字符数据或标记组成。需要对这样的标签符号进行转义即可。
补充知识:mybatis + mybatis plus + mysql——查询语句中字段名为mysql关键字问题解决方案
问题描述
### cause: com.mysql.jdbc.exceptions.jdbc4.mysqlsyntaxerrorexception: you have an error in your sql syntax; check the manual that corresponds to your mysql server version for the right syntax to use near 'desc,username,create_time,update_time from test where id=1' at line 1 ; bad sql grammar []; nested exception is com.mysql.jdbc.exceptions.jdbc4.mysqlsyntaxerrorexception: you have an error in your sql syntax; check the manual that corresponds to your mysql server version for the right syntax to use near 'desc,username,create_time,update_time from test where id=1' at line 1] with root cause
com.mysql.jdbc.exceptions.jdbc4.mysqlsyntaxerrorexception: you have an error in your sql syntax; check the manual that corresponds to your mysql server version for the right syntax to use near 'desc,username,create_time,update_time from test where id=1' at line 1
问题分析
数据库表中将sql关键字作为字段名时,在查询的时候mysql无法进行正常查询。
maven <dependency> <groupid>org.mybatis.spring.boot</groupid> <artifactid>mybatis-spring-boot-starter</artifactid> <version>2.1.2</version> </dependency> <!--mybatis-plus--> <dependency> <groupid>com.baomidou</groupid> <artifactid>mybatis-plus-boot-starter</artifactid> <version>3.3.1.tmp</version> </dependency>
解决方案
xml
错误:delete = #{delete}
正确:`delete` = #{delete}
注解
在@tablefield注解中加入反引号“ ` ”
@tablefield("`function`")
private string function;
以上这篇在mybatis @select注解中实现拼写动态sql就是小编分享给大家的全部内容了,希望能给大家一个参考,也希望大家多多支持。