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：

  1.      <insert id="insertsysUser" parameterType="com.goku.mybatis.model.sysUser">
  2.       insert into sys_user (id, username, password,
  3.        name, sex, status, org_id,
  4.        email, idcard, is_admin,
  5.        sort, mobile, stationid
  6.        )
  7.      values (#{id,jdbcType=VARCHAR}, #{username,jdbcType=VARCHAR}, #{password,jdbcType=VARCHAR},
  8.        #{name,jdbcType=VARCHAR}, #{sex,jdbcType=VARCHAR}, #{status,jdbcType=CHAR}, #{orgId,jdbcType=VARCHAR},
  9.        #{email,jdbcType=VARCHAR}, #{idcard,jdbcType=VARCHAR}, #{isAdmin,jdbcType=VARCHAR},
  10.        #{sort,jdbcType=BIGINT}, #{mobile,jdbcType=VARCHAR}, #{stationid,jdbcType=LONGVARCHAR}
  11.        )
  12.      </insert>

同时在 sysUserExtMapper.java接口中添加相应的方法

  1.  package com.goku.mybatis.mapper.ext;
  2.  
  3.  import com.goku.mybatis.model.sysUser;
  4.  import org.apache.ibatis.annotations.Param;
  5.  
  6.  import java.util.List;
  7.  import java.util.Map;
  8.  
  9.  /**
  10.   * Created by nbfujx on 2017/10/14.
  11.   */
  12.  public interface sysUserExtMapper {
  13.  
  14.      int  insertsysUser(sysUser sysuser));
  15.  }

增加相对应单元测试查看相关效果

  1.  package test.com.goku.mybatis.mapper.ext;
  2.  
  3.  import com.goku.mybatis.WebapiApplication;
  4.  import com.goku.mybatis.mapper.ext.sysUserExtMapper;
  5.  import com.goku.mybatis.model.sysUser;
  6.  import com.goku.mybatis.service.impl.sysUserServiceImpl;
  7.  import org.junit.Test;
  8.  import org.junit.runner.RunWith;
  9.  import org.slf4j.Logger;
  10.  import org.slf4j.LoggerFactory;
  11.  import org.springframework.beans.factory.annotation.Autowired;
  12.  import org.springframework.boot.test.context.SpringBootTest;
  13.  import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
  14.  
  15.  import static org.junit.Assert.*;
  16.  
  17.  /**
  18.   * Created by nbfujx on 2017/10/23.
  19.   */
  20.  @RunWith(SpringJUnit4ClassRunner.class)
  21.  @SpringBootTest(classes = WebapiApplication.class)
  22.  public class sysUserExtMapperTest  {
  23.  
  24.      private Logger logger = LoggerFactory.getLogger(sysUserExtMapperTest.class);
  25.  
  26.      @Autowired
  27.      private sysUserExtMapper sysuserextmapper;
  28.  
  29.      @Test
  30.      public void insertsysUser() throws Exception {
  31.         sysUser sysuser=new sysUser();
  32.          sysuser.setId("222");
  33.          sysuser.setOrgId("2");
  34.          int i=sysuserextmapper.insertsysUser(sysuser);
  35.          this.logger.info("执行成功个数："+i);
  36.      }
  37.  
  38.  }

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：

  1.      <insert id="insertsysUser2" parameterType="com.goku.mybatis.model.sysUser" useGeneratedKeys="true"
  2.              keyProperty="id">
  3.          insert into sys_user ( username, password,
  4.          name, sex, status, org_id,
  5.          email, idcard, is_admin,
  6.          sort, mobile, stationid
  7.          )
  8.          values ( #{username,jdbcType=VARCHAR}, #{password,jdbcType=VARCHAR},
  9.          #{name,jdbcType=VARCHAR}, #{sex,jdbcType=VARCHAR}, #{status,jdbcType=CHAR}, #{orgId,jdbcType=VARCHAR},
  10.          #{email,jdbcType=VARCHAR}, #{idcard,jdbcType=VARCHAR}, #{isAdmin,jdbcType=VARCHAR},
  11.          #{sort,jdbcType=BIGINT}, #{mobile,jdbcType=VARCHAR}, #{stationid,jdbcType=LONGVARCHAR}
  12.          )
  13.      </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：

  1.   <insert id="insertsysUser3" parameterType="com.goku.mybatis.model.sysUser">
  2.          <selectKey keyProperty="id" resultType="java.lang.String" order="BEFORE">
  3.                SELECT replace(uuid(),'-','')  AS id
  4.          </selectKey>
  5.          insert into sys_user (id, username, password,
  6.          name, sex, status, org_id,
  7.          email, idcard, is_admin,
  8.          sort, mobile, stationid
  9.          )
  10.          values (#{id,jdbcType=VARCHAR}, #{username,jdbcType=VARCHAR}, #{password,jdbcType=VARCHAR},
  11.          #{name,jdbcType=VARCHAR}, #{sex,jdbcType=VARCHAR}, #{status,jdbcType=CHAR}, #{orgId,jdbcType=VARCHAR},
  12.          #{email,jdbcType=VARCHAR}, #{idcard,jdbcType=VARCHAR}, #{isAdmin,jdbcType=VARCHAR},
  13.          #{sort,jdbcType=BIGINT}, #{mobile,jdbcType=VARCHAR}, #{stationid,jdbcType=LONGVARCHAR}
  14.          )
  15.      </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：

  1.      <update id="updateUser" parameterType="com.goku.mybatis.model.sysUser">
  2.          <!--
  3.            WARNING - @mbg.generated
  4.            This element is automatically generated by MyBatis Generator, do not modify.
  5.          -->
  6.          update sys_user
  7.          set username = #{username,jdbcType=VARCHAR},
  8.          password = #{password,jdbcType=VARCHAR},
  9.          name = #{name,jdbcType=VARCHAR},
  10.          sex = #{sex,jdbcType=VARCHAR},
  11.          status = #{status,jdbcType=CHAR},
  12.          org_id = #{orgId,jdbcType=VARCHAR},
  13.          email = #{email,jdbcType=VARCHAR},
  14.          idcard = #{idcard,jdbcType=VARCHAR},
  15.          is_admin = #{isAdmin,jdbcType=VARCHAR},
  16.          sort = #{sort,jdbcType=BIGINT},
  17.          mobile = #{mobile,jdbcType=VARCHAR},
  18.          stationid = #{stationid,jdbcType=LONGVARCHAR}
  19.          where id = #{id,jdbcType=VARCHAR}
  20.      </update>

同时在映射器接口中添加相应的方法

  1.      int updateUser(sysUser sysuser);

增加相对应单元测试查看相关效果

  1.   @Test
  2.      public void updateUser() throws Exception {
  3.          sysUser sysuser=sysuserextmapper.selectByUsername("1");
  4.          sysuser.setPassword("3");
  5.          sysuser.setOrgId("2");
  6.          int i=sysuserextmapper.updateUser(sysuser);
  7.          this.logger.info("执行成功个数："+i);
  8.      }

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：

  1.      <delete id="deleteByUserName" parameterType="java.lang.String">
  2.          <!--
  3.            WARNING - @mbg.generated
  4.            This element is automatically generated by MyBatis Generator, do not modify.
  5.          -->
  6.          delete from sys_user
  7.          where username = #{username,jdbcType=VARCHAR}
  8.      </delete>

同时在映射器接口中添加相应的方法

  1.      int deleteByUserName(@Param("username") String username);

增加相对应单元测试查看相关效果

  1.   @Test
  2.      public void deleteByUserName() throws Exception {
  3.          int i=sysuserextmapper.deleteByUserName("1");
  4.          this.logger.info("执行成功个数："+i);
  5.      }

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：

  1.     <select id="selectByUsername" parameterType="java.lang.String" resultMap="BaseResultExtMap">
  2.          select
  3.          <include refid="Base_Ext_Column_List" />
  4.          from sys_user
  5.          where username = #{username,jdbcType=VARCHAR}
  6.      </select>

同时在映射器接口中添加相应的方法

  1.      sysUser selectByUsername(String username);

增加相对应单元测试查看相关效果

  1.    @Test
  2.      public void selectByUsername() throws Exception {
  3.          sysUser user= sysuserextmapper.selectByUsername("444");
  4.          System.out.println(user.getId());
  5.      }

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。

  1.   <select id="selectByUsername" parameterType="java.lang.String" resultMap="BaseResultExtMap">
  2.          select
  3.          <include refid="Base_Ext_Column_List" />
  4.          from sys_user
  5.          where username = #{username,jdbcType=VARCHAR}
  6.      </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：

  1.      <select id="selectUserByUsername"  resultType="java.util.HashMap">
  2.          select  username,password from sys_user where username = #{username,jdbcType=VARCHAR}
  3.      </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

  1.      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：

  1.      <select id="selectUserByOrgid"  resultType="java.util.HashMap">
  2.          select  username,password from sys_user where org_id = #{orgid,jdbcType=VARCHAR}
  3.          <if test="orderFiled != null" >
  4.              order by  ${orderFiled}
  5.              <if test="orderSort != null" >
  6.                  ${orderSort}
  7.              </if>
  8.          </if>
  9.      </select>

映射器接口中添加相应的方法

  1.  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

  1.   private sysUserInfo sysuserinfo;
  2.  
  3.      public sysUserInfo getSysuserinfo() {
  4.          return sysuserinfo;
  5.      }
  6.  
  7.      public void setSysuserinfo(sysUserInfo sysuserinfo) {
  8.          this.sysuserinfo = sysuserinfo;
  9.      }

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。

  1.    <resultMap id="UserinfoBaseResultExtMap" type="com.goku.mybatis.model.sysUser" extends="BaseResultExtMap">
  2.          <!--
  3.            WARNING - @mbg.generated
  4.            This element is automatically generated by MyBatis Generator, do not modify.
  5.          -->
  6.          <result column="address" jdbcType="VARCHAR" property="sysuserinfo.address" />
  7.          <result column="post_code" jdbcType="VARCHAR" property="sysuserinfo.postCode" />
  8.          <result column="height" jdbcType="VARCHAR" property="sysuserinfo.height" />
  9.          <result column="weight" jdbcType="VARCHAR" property="sysuserinfo.weight" />
  10.          <result column="birthday" jdbcType="DATE" property="sysuserinfo.birthday" />
  11.          <result column="blood" jdbcType="VARCHAR" property="sysuserinfo.blood" />
  12.          <result column="culture" jdbcType="VARCHAR" property="sysuserinfo.culture" />
  13.          <result column="finish_school_date" jdbcType="DATE" property="sysuserinfo.finishSchoolDate" />
  14.          <result column="folk" jdbcType="VARCHAR" property="sysuserinfo.folk" />
  15.          <result column="government" jdbcType="VARCHAR" property="sysuserinfo.government" />
  16.          <result column="homepage" jdbcType="VARCHAR" property="sysuserinfo.homepage" />
  17.          <result column="householder" jdbcType="VARCHAR" property="sysuserinfo.householder" />
  18.          <result column="marriage" jdbcType="VARCHAR" property="sysuserinfo.marriage" />
  19.          <result column="msn" jdbcType="VARCHAR" property="sysuserinfo.msn" />
  20.          <result column="nativity_address" jdbcType="VARCHAR" property="sysuserinfo.nativityAddress" />
  21.          <result column="qq" jdbcType="VARCHAR" property="sysuserinfo.qq" />
  22.          <result column="speciality" jdbcType="VARCHAR" property="sysuserinfo.speciality" />
  23.          <result column="description" jdbcType="VARCHAR" property="sysuserinfo.description" />
  24.          <result column="version" jdbcType="BIGINT" property="sysuserinfo.version" />
  25.      </resultMap >

扩展方法来使用它

  1.   <select id="selectextends" parameterType="java.lang.String" resultMap="UserinfoBaseResultExtMap">
  2.          select
  3.           u.id, username, password, name, sex, status, org_id, email, idcard, is_admin, sort,
  4.          mobile,address, post_code, height, weight, birthday, blood, culture, finish_school_date,
  5.          folk, government, homepage, householder, marriage, msn, nativity_address, qq, speciality,
  6.          description, version
  7.          from sys_user u LEFT OUTER JOIN sys_user_info ui ON  u.id=ui.id
  8.             where username = #{username,jdbcType=VARCHAR}
  9.      </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。

  1.   <resultMap id="BaseResultExtMapext" type="com.goku.mybatis.model.sysUser">
  2.          <id column="id" jdbcType="VARCHAR" property="id" />
  3.          <result column="username" jdbcType="VARCHAR" property="username" />
  4.          <result column="password" jdbcType="VARCHAR" property="password" />
  5.          <result column="name" jdbcType="VARCHAR" property="name" />
  6.          <result column="sex" jdbcType="VARCHAR" property="sex" />
  7.          <result column="status" jdbcType="CHAR" property="status" />
  8.          <result column="org_id" jdbcType="VARCHAR" property="orgId" />
  9.          <result column="email" jdbcType="VARCHAR" property="email" />
  10.          <result column="idcard" jdbcType="VARCHAR" property="idcard" />
  11.          <result column="is_admin" jdbcType="VARCHAR" property="isAdmin" />
  12.          <result column="sort" jdbcType="BIGINT" property="sort" />
  13.          <result column="mobile" jdbcType="VARCHAR" property="mobile" />
  14.          <result column="address" jdbcType="VARCHAR" property="sysuserinfo.address" />
  15.          <result column="height" jdbcType="VARCHAR" property="sysuserinfo.height" />
  16.          <result column="weight" jdbcType="VARCHAR" property="sysuserinfo.weight" />
  17.          <result column="birthday" jdbcType="DATE" property="sysuserinfo.birthday" />
  18.          <result column="blood" jdbcType="VARCHAR" property="sysuserinfo.blood" />
  19.          <result column="culture" jdbcType="VARCHAR" property="sysuserinfo.culture" />
  20.          <result column="finish_school_date" jdbcType="DATE" property="sysuserinfo.finishSchoolDate" />
  21.          <result column="folk" jdbcType="VARCHAR" property="sysuserinfo.folk" />
  22.          <result column="government" jdbcType="VARCHAR" property="sysuserinfo.government" />
  23.          <result column="homepage" jdbcType="VARCHAR" property="sysuserinfo.homepage" />
  24.          <result column="householder" jdbcType="VARCHAR" property="sysuserinfo.householder" />
  25.          <result column="marriage" jdbcType="VARCHAR" property="sysuserinfo.marriage" />
  26.          <result column="msn" jdbcType="VARCHAR" property="sysuserinfo.msn" />
  27.          <result column="nativity_address" jdbcType="VARCHAR" property="sysuserinfo.nativityAddress" />
  28.          <result column="qq" jdbcType="VARCHAR" property="sysuserinfo.qq" />
  29.          <result column="speciality" jdbcType="VARCHAR" property="sysuserinfo.speciality" />
  30.          <result column="description" jdbcType="VARCHAR" property="sysuserinfo.description" />
  31.          <result column="version" jdbcType="BIGINT" property="sysuserinfo.version" />
  32.      </resultMap >

扩展方法来使用它

  1.      <select id="selectextends2" parameterType="java.lang.String" resultMap="BaseResultExtMapext">
  2.          select
  3.          u.id, username, password, name, sex, status, org_id, email, idcard, is_admin, sort,
  4.          mobile,address, post_code, height, weight, birthday, blood, culture, finish_school_date,
  5.          folk, government, homepage, householder, marriage, msn, nativity_address, qq, speciality,
  6.          description, version
  7.          from sys_user u LEFT OUTER JOIN sys_user_info ui ON  u.id=ui.id
  8.          where username = #{username,jdbcType=VARCHAR}
  9.      </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

  1.        <resultMap id="userinfoBaseResultMap" type="com.goku.mybatis.model.sysUserInfo">
  2.          <!--
  3.            WARNING - @mbg.generated
  4.            This element is automatically generated by MyBatis Generator, do not modify.
  5.          -->
  6.          <id column="id" jdbcType="VARCHAR" property="id" />
  7.          <result column="address" jdbcType="VARCHAR" property="address" />
  8.          <result column="post_code" jdbcType="VARCHAR" property="postCode" />
  9.          <result column="height" jdbcType="VARCHAR" property="height" />
  10.          <result column="weight" jdbcType="VARCHAR" property="weight" />
  11.          <result column="birthday" jdbcType="DATE" property="birthday" />
  12.          <result column="blood" jdbcType="VARCHAR" property="blood" />
  13.          <result column="culture" jdbcType="VARCHAR" property="culture" />
  14.          <result column="finish_school_date" jdbcType="DATE" property="finishSchoolDate" />
  15.          <result column="folk" jdbcType="VARCHAR" property="folk" />
  16.          <result column="government" jdbcType="VARCHAR" property="government" />
  17.          <result column="homepage" jdbcType="VARCHAR" property="homepage" />
  18.          <result column="householder" jdbcType="VARCHAR" property="householder" />
  19.          <result column="marriage" jdbcType="VARCHAR" property="marriage" />
  20.          <result column="msn" jdbcType="VARCHAR" property="msn" />
  21.          <result column="nativity_address" jdbcType="VARCHAR" property="nativityAddress" />
  22.          <result column="qq" jdbcType="VARCHAR" property="qq" />
  23.          <result column="speciality" jdbcType="VARCHAR" property="speciality" />
  24.          <result column="description" jdbcType="VARCHAR" property="description" />
  25.          <result column="version" jdbcType="BIGINT" property="version" />
  26.      </resultMap>
  27.    <resultMap type="com.goku.mybatis.model.sysUser" id="BaseResultExtMapext3">
  28.          <id column="id" jdbcType="VARCHAR" property="id" />
  29.          <result column="username" jdbcType="VARCHAR" property="username" />
  30.          <result column="password" jdbcType="VARCHAR" property="password" />
  31.          <result column="name" jdbcType="VARCHAR" property="name" />
  32.          <result column="sex" jdbcType="VARCHAR" property="sex" />
  33.          <result column="status" jdbcType="CHAR" property="status" />
  34.          <result column="org_id" jdbcType="VARCHAR" property="orgId" />
  35.          <result column="email" jdbcType="VARCHAR" property="email" />
  36.          <result column="idcard" jdbcType="VARCHAR" property="idcard" />
  37.          <result column="is_admin" jdbcType="VARCHAR" property="isAdmin" />
  38.          <result column="sort" jdbcType="BIGINT" property="sort" />
  39.          <result column="mobile" jdbcType="VARCHAR" property="mobile" />
  40.          <association property="sysuserinfo" resultMap="userinfoBaseResultMap" />
  41.      </resultMap>

相对应的扩展方法来使用它

  1.      <select id="selectextends5" parameterType="java.lang.String" resultMap="BaseResultExtMapext3">
  2.          select
  3.          u.id, username, password, name, sex, status, org_id, email, idcard, is_admin, sort,
  4.          mobile,address, post_code, height, weight, birthday, blood, culture, finish_school_date,
  5.          folk, government, homepage, householder, marriage, msn, nativity_address, qq, speciality,
  6.          description, version
  7.          from sys_user u LEFT OUTER JOIN sys_user_info ui ON  u.id=ui.id
  8.          where username = #{username,jdbcType=VARCHAR}
  9.      </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。

  1.  <resultMap type="com.goku.mybatis.model.sysUser" id="BaseResultExtMapext4">
  2.          <id column="id" jdbcType="VARCHAR" property="id" />
  3.          <result column="username" jdbcType="VARCHAR" property="username" />
  4.          <result column="password" jdbcType="VARCHAR" property="password" />
  5.          <result column="name" jdbcType="VARCHAR" property="name" />
  6.          <result column="sex" jdbcType="VARCHAR" property="sex" />
  7.          <result column="status" jdbcType="CHAR" property="status" />
  8.          <result column="org_id" jdbcType="VARCHAR" property="orgId" />
  9.          <result column="email" jdbcType="VARCHAR" property="email" />
  10.          <result column="idcard" jdbcType="VARCHAR" property="idcard" />
  11.          <result column="is_admin" jdbcType="VARCHAR" property="isAdmin" />
  12.          <result column="sort" jdbcType="BIGINT" property="sort" />
  13.          <result column="mobile" jdbcType="VARCHAR" property="mobile" />
  14.          <association property="sysuserinfo" javaType="com.goku.mybatis.model.sysUserInfo">
  15.              <id column="id" jdbcType="VARCHAR" property="id" />
  16.              <result column="address" jdbcType="VARCHAR" property="address" />
  17.              <result column="post_code" jdbcType="VARCHAR" property="postCode" />
  18.              <result column="height" jdbcType="VARCHAR" property="height" />
  19.              <result column="weight" jdbcType="VARCHAR" property="weight" />
  20.              <result column="birthday" jdbcType="DATE" property="birthday" />
  21.              <result column="blood" jdbcType="VARCHAR" property="blood" />
  22.              <result column="culture" jdbcType="VARCHAR" property="culture" />
  23.              <result column="finish_school_date" jdbcType="DATE" property="finishSchoolDate" />
  24.              <result column="folk" jdbcType="VARCHAR" property="folk" />
  25.              <result column="government" jdbcType="VARCHAR" property="government" />
  26.              <result column="homepage" jdbcType="VARCHAR" property="homepage" />
  27.              <result column="householder" jdbcType="VARCHAR" property="householder" />
  28.              <result column="marriage" jdbcType="VARCHAR" property="marriage" />
  29.              <result column="msn" jdbcType="VARCHAR" property="msn" />
  30.              <result column="nativity_address" jdbcType="VARCHAR" property="nativityAddress" />
  31.              <result column="qq" jdbcType="VARCHAR" property="qq" />
  32.              <result column="speciality" jdbcType="VARCHAR" property="speciality" />
  33.              <result column="description" jdbcType="VARCHAR" property="description" />
  34.              <result column="version" jdbcType="BIGINT" property="version" />
  35.          </association>
  36.      </resultMap>

嵌套select查询语句

  1.      <resultMap type="com.goku.mybatis.model.sysUser" id="BaseResultExtMapext2">
  2.          <id column="id" jdbcType="VARCHAR" property="id" />
  3.          <result column="username" jdbcType="VARCHAR" property="username" />
  4.          <result column="password" jdbcType="VARCHAR" property="password" />
  5.          <result column="name" jdbcType="VARCHAR" property="name" />
  6.          <result column="sex" jdbcType="VARCHAR" property="sex" />
  7.          <result column="status" jdbcType="CHAR" property="status" />
  8.          <result column="org_id" jdbcType="VARCHAR" property="orgId" />
  9.          <result column="email" jdbcType="VARCHAR" property="email" />
  10.          <result column="idcard" jdbcType="VARCHAR" property="idcard" />
  11.          <result column="is_admin" jdbcType="VARCHAR" property="isAdmin" />
  12.          <result column="sort" jdbcType="BIGINT" property="sort" />
  13.          <result column="mobile" jdbcType="VARCHAR" property="mobile" />
  14.          <association property="sysuserinfo" column="id" select="findsysUserInfoById"/>
  15.      </resultMap>

相对应的扩展方法来使用它

  1.      <select id="findsysUserInfoById" parameterType="String"
  2.              resultMap="userinfoBaseResultMap">
  3.          SELECT * FROM  sys_user_info where id = #{id,jdbcType=VARCHAR}
  4.      </select>
  5.      <select id="selectextends4" parameterType="java.lang.String" resultMap="BaseResultExtMapext2">
  6.          select *  from sys_user  where username = #{username,jdbcType=VARCHAR}
  7.      </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。

  1.      public List<sysUser> getSysuser() {
  2.          return sysuser;
  3.      }
  4.  
  5.      public void setSysuser(List<sysUser> sysuser) {
  6.          this.sysuser = sysuser;
  7.      }
  8.  
  9.      private  List<sysUser> sysuser;
使用内嵌结果ResultMap实现一对多映射
  1.      <resultMap id="OrgBaseResultMapext1" type="com.goku.mybatis.model.sysOrg">
  2.          <!--
  3.            WARNING - @mbg.generated
  4.            This element is automatically generated by MyBatis Generator, do not modify.
  5.          -->
  6.          <id column="id" jdbcType="VARCHAR" property="id" />
  7.          <result column="version" jdbcType="BIGINT" property="version" />
  8.          <result column="level" jdbcType="BIGINT" property="level" />
  9.          <result column="type" jdbcType="CHAR" property="type" />
  10.          <result column="description" jdbcType="VARCHAR" property="description" />
  11.          <result column="image" jdbcType="VARCHAR" property="image" />
  12.          <result column="isparent" jdbcType="VARCHAR" property="isparent" />
  13.          <result column="name" jdbcType="VARCHAR" property="name" />
  14.          <result column="sort" jdbcType="BIGINT" property="sort" />
  15.          <result column="url" jdbcType="VARCHAR" property="url" />
  16.          <result column="parent_id" jdbcType="VARCHAR" property="parentId" />
  17.          <result column="operate" jdbcType="VARCHAR" property="operate" />
  18.          <collection  property="sysuser" resultMap="userBaseResultMap" />
  19.      </resultMap>

相对应的扩展方法来使用它

  1.      <select id="selectextend1" parameterType="java.lang.String" resultMap="OrgBaseResultMapext1">
  2.              select   o.id, version, level, type, description, image, isparent, o.name, o.sort, url, parent_id,
  3.               u.id as uid, username, password, u.name, sex, status, org_id, email, idcard, is_admin, u.sort,
  4.                  mobile from sys_org o LEFT OUTER JOIN sys_user u
  5.              on o.id=u.org_id where o.id = #{id,jdbcType=VARCHAR}
  6.      </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
  1.   <resultMap id="OrgBaseResultMapext2" type="com.goku.mybatis.model.sysOrg">
  2.          <!--
  3.            WARNING - @mbg.generated
  4.            This element is automatically generated by MyBatis Generator, do not modify.
  5.          -->
  6.          <id column="id" jdbcType="VARCHAR" property="id" />
  7.          <result column="version" jdbcType="BIGINT" property="version" />
  8.          <result column="level" jdbcType="BIGINT" property="level" />
  9.          <result column="type" jdbcType="CHAR" property="type" />
  10.          <result column="description" jdbcType="VARCHAR" property="description" />
  11.          <result column="image" jdbcType="VARCHAR" property="image" />
  12.          <result column="isparent" jdbcType="VARCHAR" property="isparent" />
  13.          <result column="name" jdbcType="VARCHAR" property="name" />
  14.          <result column="sort" jdbcType="BIGINT" property="sort" />
  15.          <result column="url" jdbcType="VARCHAR" property="url" />
  16.          <result column="parent_id" jdbcType="VARCHAR" property="parentId" />
  17.          <result column="operate" jdbcType="VARCHAR" property="operate" />
  18.          <collection  property="sysuser" column="id" select="findsysUserByOrgId"  />
  19.      </resultMap>

相对应的扩展方法来使用它

  1.      <select id="findsysUserByOrgId" parameterType="String"
  2.              resultMap="userBaseResultMap">
  3.          SELECT * FROM  sys_user where org_id = #{id,jdbcType=VARCHAR}
  4.      </select>
  5.      <select id="selectextend2" parameterType="java.lang.String" resultMap="OrgBaseResultMapext2">
  6.          select * from sys_org where id = #{id,jdbcType=VARCHAR}
  7.      </select>

GITHUB

github :  https://github.com/nbfujx/learn-java-demo/tree/master/Goku.MybatisDemo.XML

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