Mybatis基于XML配置SQL映射器(二)
Mybatis之XML注解
之前已经讲到通过 mybatis-generator 生成mapper映射接口和相关的映射配置文件:
下面我们将详细的讲解具体内容
首先我们新建映射接口文档 sysUserExtMapper.java,同时新增相关配置文件sysUserExtMapper.xml。通过操作这两个类我们来讲解具体内容。
映射语句
MyBatis提供了多种元素来配置不同类型的语句,如SELECT,INSERT,UPDATE,DELETE。接下来让我们看看如何具体配置映射语句。
INSERT语句
一个INSERT SQL语句可以在<insert>元素在sysUserExtMapper.xml中配置,如下所示:
- <insert id="insertsysUser" parameterType="com.goku.mybatis.model.sysUser">
- insert into sys_user (id, username, password,
- name, sex, status, org_id,
- email, idcard, is_admin,
- sort, mobile, stationid
- )
- values (#{id,jdbcType=VARCHAR}, #{username,jdbcType=VARCHAR}, #{password,jdbcType=VARCHAR},
- #{name,jdbcType=VARCHAR}, #{sex,jdbcType=VARCHAR}, #{status,jdbcType=CHAR}, #{orgId,jdbcType=VARCHAR},
- #{email,jdbcType=VARCHAR}, #{idcard,jdbcType=VARCHAR}, #{isAdmin,jdbcType=VARCHAR},
- #{sort,jdbcType=BIGINT}, #{mobile,jdbcType=VARCHAR}, #{stationid,jdbcType=LONGVARCHAR}
- )
- </insert>
同时在 sysUserExtMapper.java接口中添加相应的方法
- package com.goku.mybatis.mapper.ext;
- import com.goku.mybatis.model.sysUser;
- import org.apache.ibatis.annotations.Param;
- import java.util.List;
- import java.util.Map;
- /**
- * Created by nbfujx on 2017/10/14.
- */
- public interface sysUserExtMapper {
- int insertsysUser(sysUser sysuser));
- }
增加相对应单元测试查看相关效果
- package test.com.goku.mybatis.mapper.ext;
- import com.goku.mybatis.WebapiApplication;
- import com.goku.mybatis.mapper.ext.sysUserExtMapper;
- import com.goku.mybatis.model.sysUser;
- import com.goku.mybatis.service.impl.sysUserServiceImpl;
- import org.junit.Test;
- import org.junit.runner.RunWith;
- import org.slf4j.Logger;
- import org.slf4j.LoggerFactory;
- import org.springframework.beans.factory.annotation.Autowired;
- import org.springframework.boot.test.context.SpringBootTest;
- import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
- import static org.junit.Assert.*;
- /**
- * Created by nbfujx on 2017/10/23.
- */
- @RunWith(SpringJUnit4ClassRunner.class)
- @SpringBootTest(classes = WebapiApplication.class)
- public class sysUserExtMapperTest {
- private Logger logger = LoggerFactory.getLogger(sysUserExtMapperTest.class);
- @Autowired
- private sysUserExtMapper sysuserextmapper;
- @Test
- public void insertsysUser() throws Exception {
- sysUser sysuser=new sysUser();
- sysuser.setId("222");
- sysuser.setOrgId("2");
- int i=sysuserextmapper.insertsysUser(sysuser);
- this.logger.info("执行成功个数:"+i);
- }
- }
执行效果
【自动生成主键】
在上述的INSERT语句中,我们为可以自动生成(auto-generated)主键的列 id 插入值。
我们可以使用useGeneratedKeys 和 keyProperty属性让数据库生成AUTO_INCREMENT列的值,并将生成的值设置到其中一个输入对象属性内,如下所示:
- <insert id="insertsysUser2" parameterType="com.goku.mybatis.model.sysUser" useGeneratedKeys="true"
- keyProperty="id">
- insert into sys_user ( username, password,
- name, sex, status, org_id,
- email, idcard, is_admin,
- sort, mobile, stationid
- )
- values ( #{username,jdbcType=VARCHAR}, #{password,jdbcType=VARCHAR},
- #{name,jdbcType=VARCHAR}, #{sex,jdbcType=VARCHAR}, #{status,jdbcType=CHAR}, #{orgId,jdbcType=VARCHAR},
- #{email,jdbcType=VARCHAR}, #{idcard,jdbcType=VARCHAR}, #{isAdmin,jdbcType=VARCHAR},
- #{sort,jdbcType=BIGINT}, #{mobile,jdbcType=VARCHAR}, #{stationid,jdbcType=LONGVARCHAR}
- )
- </insert>
有些数据库如Oracle并不支持 AUTO_INCREMENT 列,其使用序列(SEQUENCE),或者其他查询(uuid)来生成主键值,如下所示:
- <insert id="insertsysUser3" parameterType="com.goku.mybatis.model.sysUser">
- <selectKey keyProperty="id" resultType="java.lang.String" order="BEFORE">
- SELECT replace(uuid(),'-','') AS id
- </selectKey>
- insert into sys_user (id, username, password,
- name, sex, status, org_id,
- email, idcard, is_admin,
- sort, mobile, stationid
- )
- values (#{id,jdbcType=VARCHAR}, #{username,jdbcType=VARCHAR}, #{password,jdbcType=VARCHAR},
- #{name,jdbcType=VARCHAR}, #{sex,jdbcType=VARCHAR}, #{status,jdbcType=CHAR}, #{orgId,jdbcType=VARCHAR},
- #{email,jdbcType=VARCHAR}, #{idcard,jdbcType=VARCHAR}, #{isAdmin,jdbcType=VARCHAR},
- #{sort,jdbcType=BIGINT}, #{mobile,jdbcType=VARCHAR}, #{stationid,jdbcType=LONGVARCHAR}
- )
- </insert>
UPDATE 语句
一个UPDATE SQL语句可以在<update>元素在映射器XML配置文件中配置,如下所示:
- <update id="updateUser" parameterType="com.goku.mybatis.model.sysUser">
- <!--
- WARNING - @mbg.generated
- This element is automatically generated by MyBatis Generator, do not modify.
- -->
- update sys_user
- set username = #{username,jdbcType=VARCHAR},
- password = #{password,jdbcType=VARCHAR},
- name = #{name,jdbcType=VARCHAR},
- sex = #{sex,jdbcType=VARCHAR},
- status = #{status,jdbcType=CHAR},
- org_id = #{orgId,jdbcType=VARCHAR},
- email = #{email,jdbcType=VARCHAR},
- idcard = #{idcard,jdbcType=VARCHAR},
- is_admin = #{isAdmin,jdbcType=VARCHAR},
- sort = #{sort,jdbcType=BIGINT},
- mobile = #{mobile,jdbcType=VARCHAR},
- stationid = #{stationid,jdbcType=LONGVARCHAR}
- where id = #{id,jdbcType=VARCHAR}
- </update>
同时在映射器接口中添加相应的方法
- int updateUser(sysUser sysuser);
增加相对应单元测试查看相关效果
- @Test
- public void updateUser() throws Exception {
- sysUser sysuser=sysuserextmapper.selectByUsername("1");
- sysuser.setPassword("3");
- sysuser.setOrgId("2");
- int i=sysuserextmapper.updateUser(sysuser);
- this.logger.info("执行成功个数:"+i);
- }
测试效果
DELETE 语句
一个DELETE SQL语句可以在<delete>元素在映射器XML配置文件中配置,如下所示:
- <delete id="deleteByUserName" parameterType="java.lang.String">
- <!--
- WARNING - @mbg.generated
- This element is automatically generated by MyBatis Generator, do not modify.
- -->
- delete from sys_user
- where username = #{username,jdbcType=VARCHAR}
- </delete>
同时在映射器接口中添加相应的方法
- int deleteByUserName(@Param("username") String username);
增加相对应单元测试查看相关效果
- @Test
- public void deleteByUserName() throws Exception {
- int i=sysuserextmapper.deleteByUserName("1");
- this.logger.info("执行成功个数:"+i);
- }
测试效果
SELECT 语句
一个SELECT SQL语句可以在<select>元素在映射器XML配置文件中配置,如下所示:
- <select id="selectByUsername" parameterType="java.lang.String" resultMap="BaseResultExtMap">
- select
- <include refid="Base_Ext_Column_List" />
- from sys_user
- where username = #{username,jdbcType=VARCHAR}
- </select>
同时在映射器接口中添加相应的方法
- sysUser selectByUsername(String username);
增加相对应单元测试查看相关效果
- @Test
- public void selectByUsername() throws Exception {
- sysUser user= sysuserextmapper.selectByUsername("444");
- System.out.println(user.getId());
- }
测试效果
结果集映射ResultMaps
简单ResultMap
在<select>语句中,我们使用了resultMap属性,而不是resultType来引用映射。
当<select>语句中配置了resutlMap属性,MyBatis会使用此数据库列名与对象属性映射关系来填充JavaBean中的属性。
- <select id="selectByUsername" parameterType="java.lang.String" resultMap="BaseResultExtMap">
- select
- <include refid="Base_Ext_Column_List" />
- from sys_user
- where username = #{username,jdbcType=VARCHAR}
- </select>
让我们来看另外一个<select>映射语句定义的例子,怎样将查询结果填充到HashMap中。如下所示:
- <select id="selectUserByUsername" resultType="java.util.HashMap">
- select username,password from sys_user where username = #{username,jdbcType=VARCHAR}
- </select>
在上述的<select>语句中,我们将resultType配置成map,即java.util.HashMap的别名。在这种情况下,结果集的列名将会作为Map中的key值,而列值将作为Map的value值。
映射器接口中添加相应的方法
- Map<String, String> selectUserByUsername(@Param("username") String username);
让我们再看一个 使用resultType=”map”,返回多行结果的例子:
- <select id="selectUserByOrgid" resultType="java.util.HashMap">
- select username,password from sys_user where org_id = #{orgid,jdbcType=VARCHAR}
- <if test="orderFiled != null" >
- order by ${orderFiled}
- <if test="orderSort != null" >
- ${orderSort}
- </if>
- </if>
- </select>
映射器接口中添加相应的方法
- List<Map<String, String>> selectUserByOrgid(@Param("orgid") String orgid, @Param("orderSort") String orderSort, @Param("orderFiled") String orderFiled);
拓展ResultMap
首先我们要在 sys_User中增加 sys_user_info对象。下面同理
- private sysUserInfo sysuserinfo;
- public sysUserInfo getSysuserinfo() {
- return sysuserinfo;
- }
- public void setSysuserinfo(sysUserInfo sysuserinfo) {
- this.sysuserinfo = sysuserinfo;
- }
我们可以从从另外一个<resultMap>,拓展出一个新的<resultMap>,这样,原先的属性映射可以继承过来,以实现。
- <resultMap id="UserinfoBaseResultExtMap" type="com.goku.mybatis.model.sysUser" extends="BaseResultExtMap">
- <!--
- WARNING - @mbg.generated
- This element is automatically generated by MyBatis Generator, do not modify.
- -->
- <result column="address" jdbcType="VARCHAR" property="sysuserinfo.address" />
- <result column="post_code" jdbcType="VARCHAR" property="sysuserinfo.postCode" />
- <result column="height" jdbcType="VARCHAR" property="sysuserinfo.height" />
- <result column="weight" jdbcType="VARCHAR" property="sysuserinfo.weight" />
- <result column="birthday" jdbcType="DATE" property="sysuserinfo.birthday" />
- <result column="blood" jdbcType="VARCHAR" property="sysuserinfo.blood" />
- <result column="culture" jdbcType="VARCHAR" property="sysuserinfo.culture" />
- <result column="finish_school_date" jdbcType="DATE" property="sysuserinfo.finishSchoolDate" />
- <result column="folk" jdbcType="VARCHAR" property="sysuserinfo.folk" />
- <result column="government" jdbcType="VARCHAR" property="sysuserinfo.government" />
- <result column="homepage" jdbcType="VARCHAR" property="sysuserinfo.homepage" />
- <result column="householder" jdbcType="VARCHAR" property="sysuserinfo.householder" />
- <result column="marriage" jdbcType="VARCHAR" property="sysuserinfo.marriage" />
- <result column="msn" jdbcType="VARCHAR" property="sysuserinfo.msn" />
- <result column="nativity_address" jdbcType="VARCHAR" property="sysuserinfo.nativityAddress" />
- <result column="qq" jdbcType="VARCHAR" property="sysuserinfo.qq" />
- <result column="speciality" jdbcType="VARCHAR" property="sysuserinfo.speciality" />
- <result column="description" jdbcType="VARCHAR" property="sysuserinfo.description" />
- <result column="version" jdbcType="BIGINT" property="sysuserinfo.version" />
- </resultMap >
扩展方法来使用它
- <select id="selectextends" parameterType="java.lang.String" resultMap="UserinfoBaseResultExtMap">
- select
- u.id, username, password, name, sex, status, org_id, email, idcard, is_admin, sort,
- mobile,address, post_code, height, weight, birthday, blood, culture, finish_school_date,
- folk, government, homepage, householder, marriage, msn, nativity_address, qq, speciality,
- description, version
- from sys_user u LEFT OUTER JOIN sys_user_info ui ON u.id=ui.id
- where username = #{username,jdbcType=VARCHAR}
- </select>
一对一映射
使用嵌套结果ResultMap实现一对一关系映射
在我们的域模型样例中,每一个用户都有一个与之关联的用户扩展信息。表sys_user有一个id列,是sys_user_info表的外键。我们定义一个resultMap中,sys_user_info的属性使用了圆点记法被赋上了对应列的值。
- <resultMap id="BaseResultExtMapext" type="com.goku.mybatis.model.sysUser">
- <id column="id" jdbcType="VARCHAR" property="id" />
- <result column="username" jdbcType="VARCHAR" property="username" />
- <result column="password" jdbcType="VARCHAR" property="password" />
- <result column="name" jdbcType="VARCHAR" property="name" />
- <result column="sex" jdbcType="VARCHAR" property="sex" />
- <result column="status" jdbcType="CHAR" property="status" />
- <result column="org_id" jdbcType="VARCHAR" property="orgId" />
- <result column="email" jdbcType="VARCHAR" property="email" />
- <result column="idcard" jdbcType="VARCHAR" property="idcard" />
- <result column="is_admin" jdbcType="VARCHAR" property="isAdmin" />
- <result column="sort" jdbcType="BIGINT" property="sort" />
- <result column="mobile" jdbcType="VARCHAR" property="mobile" />
- <result column="address" jdbcType="VARCHAR" property="sysuserinfo.address" />
- <result column="height" jdbcType="VARCHAR" property="sysuserinfo.height" />
- <result column="weight" jdbcType="VARCHAR" property="sysuserinfo.weight" />
- <result column="birthday" jdbcType="DATE" property="sysuserinfo.birthday" />
- <result column="blood" jdbcType="VARCHAR" property="sysuserinfo.blood" />
- <result column="culture" jdbcType="VARCHAR" property="sysuserinfo.culture" />
- <result column="finish_school_date" jdbcType="DATE" property="sysuserinfo.finishSchoolDate" />
- <result column="folk" jdbcType="VARCHAR" property="sysuserinfo.folk" />
- <result column="government" jdbcType="VARCHAR" property="sysuserinfo.government" />
- <result column="homepage" jdbcType="VARCHAR" property="sysuserinfo.homepage" />
- <result column="householder" jdbcType="VARCHAR" property="sysuserinfo.householder" />
- <result column="marriage" jdbcType="VARCHAR" property="sysuserinfo.marriage" />
- <result column="msn" jdbcType="VARCHAR" property="sysuserinfo.msn" />
- <result column="nativity_address" jdbcType="VARCHAR" property="sysuserinfo.nativityAddress" />
- <result column="qq" jdbcType="VARCHAR" property="sysuserinfo.qq" />
- <result column="speciality" jdbcType="VARCHAR" property="sysuserinfo.speciality" />
- <result column="description" jdbcType="VARCHAR" property="sysuserinfo.description" />
- <result column="version" jdbcType="BIGINT" property="sysuserinfo.version" />
- </resultMap >
扩展方法来使用它
- <select id="selectextends2" parameterType="java.lang.String" resultMap="BaseResultExtMapext">
- select
- u.id, username, password, name, sex, status, org_id, email, idcard, is_admin, sort,
- mobile,address, post_code, height, weight, birthday, blood, culture, finish_school_date,
- folk, government, homepage, householder, marriage, msn, nativity_address, qq, speciality,
- description, version
- from sys_user u LEFT OUTER JOIN sys_user_info ui ON u.id=ui.id
- where username = #{username,jdbcType=VARCHAR}
- </select>
使用嵌套Select语句实现一对一关系映射
上述样例展示了一对一关联映射的一种方法。然而,使用这种方式映射,如果sysuserinfo结果需要在其他的SELECT映射语句中映射成Address对象,我们需要为每一个语句重复这种映射关系。MyBatis提供了更好地实现一对一关联映射的方法:嵌套结果ResultMap和嵌套select查询语句。
嵌套结果ResultMap
- <resultMap id="userinfoBaseResultMap" type="com.goku.mybatis.model.sysUserInfo">
- <!--
- WARNING - @mbg.generated
- This element is automatically generated by MyBatis Generator, do not modify.
- -->
- <id column="id" jdbcType="VARCHAR" property="id" />
- <result column="address" jdbcType="VARCHAR" property="address" />
- <result column="post_code" jdbcType="VARCHAR" property="postCode" />
- <result column="height" jdbcType="VARCHAR" property="height" />
- <result column="weight" jdbcType="VARCHAR" property="weight" />
- <result column="birthday" jdbcType="DATE" property="birthday" />
- <result column="blood" jdbcType="VARCHAR" property="blood" />
- <result column="culture" jdbcType="VARCHAR" property="culture" />
- <result column="finish_school_date" jdbcType="DATE" property="finishSchoolDate" />
- <result column="folk" jdbcType="VARCHAR" property="folk" />
- <result column="government" jdbcType="VARCHAR" property="government" />
- <result column="homepage" jdbcType="VARCHAR" property="homepage" />
- <result column="householder" jdbcType="VARCHAR" property="householder" />
- <result column="marriage" jdbcType="VARCHAR" property="marriage" />
- <result column="msn" jdbcType="VARCHAR" property="msn" />
- <result column="nativity_address" jdbcType="VARCHAR" property="nativityAddress" />
- <result column="qq" jdbcType="VARCHAR" property="qq" />
- <result column="speciality" jdbcType="VARCHAR" property="speciality" />
- <result column="description" jdbcType="VARCHAR" property="description" />
- <result column="version" jdbcType="BIGINT" property="version" />
- </resultMap>
- <resultMap type="com.goku.mybatis.model.sysUser" id="BaseResultExtMapext3">
- <id column="id" jdbcType="VARCHAR" property="id" />
- <result column="username" jdbcType="VARCHAR" property="username" />
- <result column="password" jdbcType="VARCHAR" property="password" />
- <result column="name" jdbcType="VARCHAR" property="name" />
- <result column="sex" jdbcType="VARCHAR" property="sex" />
- <result column="status" jdbcType="CHAR" property="status" />
- <result column="org_id" jdbcType="VARCHAR" property="orgId" />
- <result column="email" jdbcType="VARCHAR" property="email" />
- <result column="idcard" jdbcType="VARCHAR" property="idcard" />
- <result column="is_admin" jdbcType="VARCHAR" property="isAdmin" />
- <result column="sort" jdbcType="BIGINT" property="sort" />
- <result column="mobile" jdbcType="VARCHAR" property="mobile" />
- <association property="sysuserinfo" resultMap="userinfoBaseResultMap" />
- </resultMap>
相对应的扩展方法来使用它
- <select id="selectextends5" parameterType="java.lang.String" resultMap="BaseResultExtMapext3">
- select
- u.id, username, password, name, sex, status, org_id, email, idcard, is_admin, sort,
- mobile,address, post_code, height, weight, birthday, blood, culture, finish_school_date,
- folk, government, homepage, householder, marriage, msn, nativity_address, qq, speciality,
- description, version
- from sys_user u LEFT OUTER JOIN sys_user_info ui ON u.id=ui.id
- where username = #{username,jdbcType=VARCHAR}
- </select>
元素<association>被用来导入“有一个”(has-one)类型的关联。在上述的例子中,我们使用了<association>元素引用了另外的在同一个XML文件中定义的<resultMap>。也可以使用<association>定义内联的resultMap。
- <resultMap type="com.goku.mybatis.model.sysUser" id="BaseResultExtMapext4">
- <id column="id" jdbcType="VARCHAR" property="id" />
- <result column="username" jdbcType="VARCHAR" property="username" />
- <result column="password" jdbcType="VARCHAR" property="password" />
- <result column="name" jdbcType="VARCHAR" property="name" />
- <result column="sex" jdbcType="VARCHAR" property="sex" />
- <result column="status" jdbcType="CHAR" property="status" />
- <result column="org_id" jdbcType="VARCHAR" property="orgId" />
- <result column="email" jdbcType="VARCHAR" property="email" />
- <result column="idcard" jdbcType="VARCHAR" property="idcard" />
- <result column="is_admin" jdbcType="VARCHAR" property="isAdmin" />
- <result column="sort" jdbcType="BIGINT" property="sort" />
- <result column="mobile" jdbcType="VARCHAR" property="mobile" />
- <association property="sysuserinfo" javaType="com.goku.mybatis.model.sysUserInfo">
- <id column="id" jdbcType="VARCHAR" property="id" />
- <result column="address" jdbcType="VARCHAR" property="address" />
- <result column="post_code" jdbcType="VARCHAR" property="postCode" />
- <result column="height" jdbcType="VARCHAR" property="height" />
- <result column="weight" jdbcType="VARCHAR" property="weight" />
- <result column="birthday" jdbcType="DATE" property="birthday" />
- <result column="blood" jdbcType="VARCHAR" property="blood" />
- <result column="culture" jdbcType="VARCHAR" property="culture" />
- <result column="finish_school_date" jdbcType="DATE" property="finishSchoolDate" />
- <result column="folk" jdbcType="VARCHAR" property="folk" />
- <result column="government" jdbcType="VARCHAR" property="government" />
- <result column="homepage" jdbcType="VARCHAR" property="homepage" />
- <result column="householder" jdbcType="VARCHAR" property="householder" />
- <result column="marriage" jdbcType="VARCHAR" property="marriage" />
- <result column="msn" jdbcType="VARCHAR" property="msn" />
- <result column="nativity_address" jdbcType="VARCHAR" property="nativityAddress" />
- <result column="qq" jdbcType="VARCHAR" property="qq" />
- <result column="speciality" jdbcType="VARCHAR" property="speciality" />
- <result column="description" jdbcType="VARCHAR" property="description" />
- <result column="version" jdbcType="BIGINT" property="version" />
- </association>
- </resultMap>
嵌套select查询语句
- <resultMap type="com.goku.mybatis.model.sysUser" id="BaseResultExtMapext2">
- <id column="id" jdbcType="VARCHAR" property="id" />
- <result column="username" jdbcType="VARCHAR" property="username" />
- <result column="password" jdbcType="VARCHAR" property="password" />
- <result column="name" jdbcType="VARCHAR" property="name" />
- <result column="sex" jdbcType="VARCHAR" property="sex" />
- <result column="status" jdbcType="CHAR" property="status" />
- <result column="org_id" jdbcType="VARCHAR" property="orgId" />
- <result column="email" jdbcType="VARCHAR" property="email" />
- <result column="idcard" jdbcType="VARCHAR" property="idcard" />
- <result column="is_admin" jdbcType="VARCHAR" property="isAdmin" />
- <result column="sort" jdbcType="BIGINT" property="sort" />
- <result column="mobile" jdbcType="VARCHAR" property="mobile" />
- <association property="sysuserinfo" column="id" select="findsysUserInfoById"/>
- </resultMap>
相对应的扩展方法来使用它
- <select id="findsysUserInfoById" parameterType="String"
- resultMap="userinfoBaseResultMap">
- SELECT * FROM sys_user_info where id = #{id,jdbcType=VARCHAR}
- </select>
- <select id="selectextends4" parameterType="java.lang.String" resultMap="BaseResultExtMapext2">
- select * from sys_user where username = #{username,jdbcType=VARCHAR}
- </select>
一对多映射
我们创建一张机构表一个机构包含多个用户。在sys_org中增加sys_user对象。
- public List<sysUser> getSysuser() {
- return sysuser;
- }
- public void setSysuser(List<sysUser> sysuser) {
- this.sysuser = sysuser;
- }
- private List<sysUser> sysuser;
使用内嵌结果ResultMap实现一对多映射
- <resultMap id="OrgBaseResultMapext1" type="com.goku.mybatis.model.sysOrg">
- <!--
- WARNING - @mbg.generated
- This element is automatically generated by MyBatis Generator, do not modify.
- -->
- <id column="id" jdbcType="VARCHAR" property="id" />
- <result column="version" jdbcType="BIGINT" property="version" />
- <result column="level" jdbcType="BIGINT" property="level" />
- <result column="type" jdbcType="CHAR" property="type" />
- <result column="description" jdbcType="VARCHAR" property="description" />
- <result column="image" jdbcType="VARCHAR" property="image" />
- <result column="isparent" jdbcType="VARCHAR" property="isparent" />
- <result column="name" jdbcType="VARCHAR" property="name" />
- <result column="sort" jdbcType="BIGINT" property="sort" />
- <result column="url" jdbcType="VARCHAR" property="url" />
- <result column="parent_id" jdbcType="VARCHAR" property="parentId" />
- <result column="operate" jdbcType="VARCHAR" property="operate" />
- <collection property="sysuser" resultMap="userBaseResultMap" />
- </resultMap>
相对应的扩展方法来使用它
- <select id="selectextend1" parameterType="java.lang.String" resultMap="OrgBaseResultMapext1">
- select o.id, version, level, type, description, image, isparent, o.name, o.sort, url, parent_id,
- u.id as uid, username, password, u.name, sex, status, org_id, email, idcard, is_admin, u.sort,
- mobile from sys_org o LEFT OUTER JOIN sys_user u
- on o.id=u.org_id where o.id = #{id,jdbcType=VARCHAR}
- </select>
级联查询的时候,主表和从表有一样的字段名的时候,在mysql上命令查询是没问题的。但在mybatis中主从表需要为相同字段名设置别名。
<collection>元素被用来将多行结果映射成一个对象的一个集合。
使用嵌套Select语句实现一对多映射
- <resultMap id="OrgBaseResultMapext2" type="com.goku.mybatis.model.sysOrg">
- <!--
- WARNING - @mbg.generated
- This element is automatically generated by MyBatis Generator, do not modify.
- -->
- <id column="id" jdbcType="VARCHAR" property="id" />
- <result column="version" jdbcType="BIGINT" property="version" />
- <result column="level" jdbcType="BIGINT" property="level" />
- <result column="type" jdbcType="CHAR" property="type" />
- <result column="description" jdbcType="VARCHAR" property="description" />
- <result column="image" jdbcType="VARCHAR" property="image" />
- <result column="isparent" jdbcType="VARCHAR" property="isparent" />
- <result column="name" jdbcType="VARCHAR" property="name" />
- <result column="sort" jdbcType="BIGINT" property="sort" />
- <result column="url" jdbcType="VARCHAR" property="url" />
- <result column="parent_id" jdbcType="VARCHAR" property="parentId" />
- <result column="operate" jdbcType="VARCHAR" property="operate" />
- <collection property="sysuser" column="id" select="findsysUserByOrgId" />
- </resultMap>
相对应的扩展方法来使用它
- <select id="findsysUserByOrgId" parameterType="String"
- resultMap="userBaseResultMap">
- SELECT * FROM sys_user where org_id = #{id,jdbcType=VARCHAR}
- </select>
- <select id="selectextend2" parameterType="java.lang.String" resultMap="OrgBaseResultMapext2">
- select * from sys_org where id = #{id,jdbcType=VARCHAR}
- </select>
GITHUB
github : https://github.com/nbfujx/learn-java-demo/tree/master/Goku.MybatisDemo.XML
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