一文搞定Mybatis 一对多延迟加载，并且子查询中与主表字段不对应
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Mybatis 一对多延迟加载，并且子查询中与主表字段不对应应用说明。
实现一对多关联（懒加载），一个教研组对应多个教师，既：教师的教研编号与教研组的教研编号关联，并且教师关联教研组外键与教研组编号不一致。
1、工程资源配置文件
1）、本应用实际应用到了（开启延迟加载配置、关闭立即加载配置）；
2） 、外关联查询语句对应xml文件 :
3）、主查询xml文件：
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<settings>
<!-- 开启日志，并制定使用的具体日志,LOG4J 对应 log4j.properties的文件名 -->
<setting name="logImpl" value="LOG4J"/>
<!-- 开启延迟加载 -->
<setting name="lazyLoadingEnabled" value="true"/>
<!-- g关闭立即加载 -->
<setting name="aggressiveLazyLoading" value="false"/>
</settings>
<!-- 转换器 -->
<typeHandlers>
<!-- 把java类的boolean类型转换数据 int，数据库int转换为java类的boolean类型 -->
<typeHandler handler="com.mybatis03.util.BooleanAndIntConverter" javaType="Boolean" jdbcType="INTEGER"/>
</typeHandlers>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://127.0.0.1:3306/mybatis01"/>
<property name="username" value="root"/>
<property name="password" value="root"/>
</dataSource>
</environment>
</environments>
<mappers>
<!-- 加载映射文件 -->
<mapper resource="com/mybatis03/mapper/personMapper.xml"/>
<mapper resource="com/mybatis03/mapper/TeacherMapper.xml"/>
<mapper resource="com/mybatis03/mapper/teacherCourseMapper.xml"/>
<!-- 外关联查询语句对应xml文件 -->
<mapper resource="com/mybatis03/mapper/teacherGroupToTeacherMapper.xml"/>
</mappers>
</configuration>
2、mapper文件
2.1 教师.xml 文件
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.mybatis03.mapper.TeacherMapper">
<!-- 实现一对多关联（懒加载），一个教研组对应多个教师，既：教师的教研编号与教研组的教研编号关联 -->
<select id="queryWithLazyGroupAndTeachers" parameterType="int" resultMap="lazyGroupTeacherMap">
SELECT g.*,g.groupID AS groupno FROM teachergroup g
WHERE g.groupid =#groupid
</select>
<!--类和表对应关系 (一对多都用collection，一对一用 association) -->
<resultMap id="lazyGroupTeacherMap" type="com.mybatis03.bean.TeacherGroup">
<!-- 因为type主类是TeacherGroup，所以先配置 TeacherGroup类属性对应关系 -->
<id property="groupID" column="groupid" />
<result property="groupName" column="groupname"/>
<!-- 配置成员属性教师 ,一对多；属性类型：javaType,属性元素类型 ofType-->
<!--property 中的属性为实体类中的属性，column对应数据库中的字段 -->
<collection property="teacherList" ofType="com.mybatis03.bean.Teacher"
select="com.mybatis03.mapper.teacherGroupToTeacherMapper.queryGroupToTeacherByNO" column="groupno" >
</collection>
</resultMap>
</mapper>
说明：由于在关联过程中，教研组编号与教师编号不一致，通过重命名方式使。关联字段一致：
A、本应用实现懒加载使用原始SQL关联查询应为：SELECT g.,t. FROM teachergroup g INNER JOIN teacher t ON g.groupid = t.groupno WHERE g.groupid =#groupid
B、应用懒加载实现说明解决字段不一致参加红色浪线；
2.2 外关联查询教师信息xml文件
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!--指定为接口的全类名-->
<mapper namespace="com.mybatis03.mapper.teacherGroupToTeacherMapper">
<!-- 查询教师，延迟加载应用此配置文件 -->
<!-- 查询教师对应的课程 -->
<select id="queryGroupToTeacherByNO" parameterType="int" resultType="com.mybatis03.bean.Teacher">
SELECT * FROM teacher WHERE groupno = #groupno
</select>
</mapper>
3、教师接口类
public interface TeacherMapper
/* 实现一对多关联(延迟加载)，一个教研组对应多个教师，既：教师的教研编号与教研组的教研编号关联 */
TeacherGroup queryWithLazyGroupAndTeachers(int groupNo);
4、实体类
4.1 教师实体类
public class Teacher
@Override
public String toString()
return "Teacher" +
"teaNo=" + teaNo +
", courseNo=" + courseNo +
", teaName='" + teaName + '\\'' +
", teacherCourse" +
"courseNo=" + teacherCourse.getCourseNo() +
", courseName=" + teacherCourse.getCourseName() +""+
'';
/* 教师编号 */
private int teaNo;
/* 课程编号 */
private int courseNo;
/* 教师名称 */
private String teaName;
/* 教师课程类,课程作为老师属性 */
private TeacherCourse teacherCourse;
/* 新增一个教研组编号，用于关联教研组编号，实现多对一关联*/
private int groupNo;
/**
* <!--利用resultMap实现一对一 -->
* @return
*/
public TeacherCourse getTeacherCourse()
return teacherCourse;
public void setTeacherCourse(TeacherCourse teacherCourse)
this.teacherCourse = teacherCourse;
public int getGroupNo()
return groupNo;
public void setGroupNo(int groupNo)
this.groupNo = groupNo;
public int getCourseNo()
return courseNo;
public void setCourseNo(int courseNo)
this.courseNo = courseNo;
public int getTeaNo()
return teaNo;
public void setTeaNo(int teaNo)
this.teaNo = teaNo;
public String getTeaName()
return teaName;
public void setTeaName(String teaName)
this.teaName = teaName;
4.2 教研组实体类
public class TeacherGroup
@Override
public String toString()
String str = "";
for (int i = 0; i < teacherList.size(); i++)
str += "teaNo=" + teacherList.get(i).getTeaNo() + ",";
str += "courseNo=" + teacherList.get(i).getCourseNo() + ",";
str += "teaName=" + teacherList.get(i).getTeaName() + ",";
str += "groupNo=" + teacherList.get(i).getGroupNo();
if (i < teacherList.size() - 1)
str += ",";
return "TeacherGroup" +
"groupID=" + groupID +
", groupName='" + groupName + '\\'' +
", teacherList" +
// "teaNo=" + teacherList.get(0).getTeaNo() + "," +
// "courseNo=" + teacherList.get(0).getCourseNo() + "," +
// "teaName=" + teacherList.get(0).getTeaName() + "," +
// "groupNo=" + teacherList.get(0).getGroupNo() + "," +
str+
"" +
'';
/* 教研组编号：汉语教研组 1，英语教研组2，日语教研组3，德语教研组 4 */
/* 教研组编号，用于关联教师编号，实现多对一关联*/
private int groupID;
/* 教研组名称，英语教研组，日语教研组还是德语教研组*/
private String groupName;
/* 一个教研组对应多个教师,属于一对多关系。关联关系：教师的教研编号与教研组的教研编号关联 */
private List<Teacher> teacherList;
public List<Teacher> getTeacherList()
return teacherList;
public void setTeacherList(List<Teacher> teacherList)
this.teacherList = teacherList;
public int getGroupID()
return groupID;
public void setGroupID(int groupID)
this.groupID = groupID;
public String getGroupName()
return groupName;
public void setGroupName(String groupName)
this.groupName = groupName;
5、测试类
@Test
public void queryWithLazyGroupAndTeachers() throws Exception
Reader reader = Resources.getResourceAsReader("mybatis-03.xml");
SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader);
SqlSession session = sessionFactory.openSession();
int groupNo = 1;
TeacherMapper personMapper = session.getMapper(TeacherMapper.class);
TeacherGroup teacherGroup = personMapper.queryWithLazyGroupAndTeachers(groupNo);
System.out.println("教研组编号:"+teacherGroup.getGroupID()+",教研组名称:"+teacherGroup.getGroupName());
List<Teacher> teacherList = teacherGroup.getTeacherList();
for (Teacher teacher : teacherList)
System.out.println("教师编号:"+teacher.getTeaNo()+",教师名称:"
+teacher.getTeaName()+",教研组编号:"+teacher.getGroupNo());
测试结果
"C:\\Program Files\\Java\\jdk1.8.0_25\\bin\\java" -ea -Didea.test.cyclic.buffer.size=1048576 "-javaagent:C:\\Users\\newsoft\\AppData\\Roaming\\JetBrains\\IntelliJ IDEA 2017.3.5\\lib\\idea_rt.jar=1031:C:\\Users\\newsoft\\AppData\\Roaming\\JetBrains\\IntelliJ IDEA 2017.3.5\\bin" -Dfile.encoding=UTF-8 -classpath "C:\\Users\\newsoft\\AppData\\Roaming\\JetBrains\\IntelliJ IDEA 2017.3.5\\lib\\idea_rt.jar;C:\\Users\\newsoft\\AppData\\Roaming\\JetBrains\\IntelliJ IDEA 2017.3.5\\plugins\\junit\\lib\\junit-rt.jar;C:\\Users\\newsoft\\AppData\\Roaming\\JetBrains\\IntelliJ IDEA 2017.3.5\\plugins\\junit\\lib\\junit5-rt.jar;D:\\download\\lib\\mavenTollTransfer\\mic-repository\\org\\junit\\platform\\junit-platform-launcher\\1.5.2\\junit-platform-launcher-1.5.2.jar;D:\\download\\lib\\mavenTollTransfer\\mic-repository\\org\\apiguardian\\apiguardian-api\\1.1.0\\apiguardian-api-1.1.0.jar;D:\\download\\lib\\mavenTollTransfer\\mic-repository\\org\\junit\\platform\\junit-platform-engine\\1.5.2\\junit-platform-engine-1.5.2.jar;D:\\download\\lib\\mavenTollTransfer\\mic-repository\\org\\opentest4j\\opentest4j\\1.2.0\\opentest4j-1.2.0.jar;D:\\download\\lib\\mavenTollTransfer\\mic-repository\\org\\junit\\platform\\junit-platform-commons\\1.5.2\\junit-platform-commons-1.5.2.jar;D:\\download\\lib\\mavenTollTransfer\\mic-repository\\org\\junit\\jupiter\\junit-jupiter-engine\\5.5.2\\junit-jupiter-engine-5.5.2.jar;D:\\download\\lib\\mavenTollTransfer\\mic-repository\\org\\junit\\jupiter\\junit-jupiter-api\\5.5.2\\junit-jupiter-api-5.5.2.jar;D:\\download\\lib\\mavenTollTransfer\\mic-repository\\org\\junit\\vintage\\junit-vintage-engine\\5.5.2\\junit-vintage-engine-5.5.2.jar;D:\\download\\lib\\mavenTollTransfer\\mic-repository\\junit\\junit\\4.12\\junit-4.12.jar;D:\\download\\lib\\mavenTollTransfer\\mic-repository\\org\\hamcrest\\hamcrest-core\\1.3\\hamcrest-core-1.3.jar;C:\\Program Files\\Java\\jdk1.8.0_25\\jre\\lib\\charsets.jar;C:\\Program Files\\Java\\jdk1.8.0_25\\jre\\lib\\deploy.jar;C:\\Program Files\\Java\\jdk1.8.0_25\\jre\\lib\\ext\\access-bridge-64.jar;C:\\Program Files\\Java\\jdk1.8.0_25\\jre\\lib\\ext\\cldrdata.jar;C:\\Program Files\\Java\\jdk1.8.0_25\\jre\\lib\\ext\\dnsns.jar;C:\\Program Files\\Java\\jdk1.8.0_25\\jre\\lib\\ext\\jaccess.jar;C:\\Program Files\\Java\\jdk1.8.0_25\\jre\\lib\\ext\\jfxrt.jar;C:\\Program Files\\Java\\jdk1.8.0_25\\jre\\lib\\ext\\localedata.jar;C:\\Program Files\\Java\\jdk1.8.0_25\\jre\\lib\\ext\\nashorn.jar;C:\\Program Files\\Java\\jdk1.8.0_25\\jre\\lib\\ext\\sunec.jar;C:\\Program Files\\Java\\jdk1.8.0_25\\jre\\lib\\ext\\sunjce_provider.jar;C:\\Program Files\\Java\\jdk1.8.0_25\\jre\\lib\\ext\\sunmscapi.jar;C:\\Program Files\\Java\\jdk1.8.0_25\\jre\\lib\\ext\\sunpkcs11.jar;C:\\Program Files\\Java\\jdk1.8.0_25\\jre\\lib\\ext\\zipfs.jar;C:\\Program Files\\Java\\jdk1.8.0_25\\jre\\lib\\javaws.jar;C:\\Program Files\\Java\\jdk1.8.0_25\\jre\\lib\\jce.jar;C:\\Program Files\\Java\\jdk1.8.0_25\\jre\\lib\\jfr.jar;C:\\Program Files\\Java\\jdk1.8.0_25\\jre\\lib\\jfxswt.jar;C:\\Program Files\\Java\\jdk1.8.0_25\\jre\\lib\\jsse.jar;C:\\Program Files\\Java\\jdk1.8.0_25\\jre\\lib\\management-agent.jar;C:\\Program Files\\Java\\jdk1.8.0_25\\jre\\lib\\plugin.jar;C:\\Program Files\\Java\\jdk1.8.0_25\\jre\\lib\\resources.jar;C:\\Program Files\\Java\\jdk1.8.0_25\\jre\\lib\\rt.jar;D:\\ideaworkspace\\ProjectStudy\\mybatis-02\\target\\classes;D:\\download\\lib\\mavenTollTransfer\\mic-repository\\org\\hamcrest\\hamcrest-core\\2.1\\hamcrest-core-2.1.jar;D:\\download\\lib\\mavenTollTransfer\\mic-repository\\org\\hamcrest\\hamcrest\\2.1\\hamcrest-2.1.jar;D:\\download\\lib\\mavenTollTransfer\\mic-repository\\org\\mybatis\\mybatis\\3.4.5\\mybatis-3.4.5.jar;D:\\download\\lib\\mavenTollTransfer\\mic-repository\\mysql\\mysql-connector-java\\5.1.44\\mysql-connector-java-5.1.44.jar;D:\\download\\lib\\mavenTollTransfer\\mic-repository\\log4j\\log4j\\1.2.17\\log4j-1.2.17.jar;D:\\download\\lib\\mavenTollTransfer\\mic-repository\\org\\slf4j\\slf4j-log4j12\\1.7.12\\slf4j-log4j12-1.7.12.jar;D:\\download\\lib\\mavenTollTransfer\\mic-repository\\org\\slf4j\\slf4j-api\\1.7.30\\slf4j-api-1.7.30.jar;D:\\download\\lib\\mavenTollTransfer\\mic-repository\\cglib\\cglib\\3.3.0\\cglib-3.3.0.jar;D:\\download\\lib\\mavenTollTransfer\\mic-repository\\org\\ow2\\asm\\asm\\7.1\\asm-7.1.jar;D:\\download\\lib\\mavenTollTransfer\\mic-repository\\net\\logstash\\logback\\logstash-logback-encoder\\5.3\\logstash-logback-encoder-5.3.jar;D:\\download\\lib\\mavenTollTransfer\\mic-repository\\com\\fasterxml\\jackson\\core\\jackson-databind\\2.10.3\\jackson-databind-2.10.3.jar;D:\\download\\lib\\mavenTollTransfer\\mic-repository\\com\\fasterxml\\jackson\\core\\jackson-annotations\\2.10.3\\jackson-annotations-2.10.3.jar;D:\\download\\lib\\mavenTollTransfer\\mic-repository\\com\\fasterxml\\jackson\\core\\jackson-core\\2.10.3\\jackson-core-2.10.3.jar" com.intellij.rt.execution.junit.JUnitStarter -ideVersion5 -junit5 com.mybatis03.test.testTeacher01,queryWithLazyGroupAndTeachers
[lsjSso]2021-10-20 09:17:47,649-org.apache.ibatis.logging.LogFactory-0 [main]DEBUGorg.apache.ibatis.logging.LogFactory-Logging initialized using 'class org.apache.ibatis.logging.slf4j.Slf4jImpl' adapter.
[lsjSso]2021-10-20 09:17:47,753-org.apache.ibatis.logging.LogFactory-104 [main]DEBUGorg.apache.ibatis.logging.LogFactory-Logging initialized using 'class org.apache.ibatis.logging.log4j.Log4jImpl' adapter.
[lsjSso]2021-10-20 09:17:47,781-org.apache.ibatis.datasource.pooled.PooledDataSource-132 [main]DEBUGorg.apache.ibatis.datasource.pooled.PooledDataSource-PooledDataSource forcefully closed/removed all connections.
[lsjSso]2021-10-20 09:17:47,781-org.apache.ibatis.datasource.pooled.PooledDataSource-132 [main]DEBUGorg.apache.ibatis.datasource.pooled.PooledDataSource-PooledDataSource forcefully closed/removed all connections.
[lsjSso]2021-10-20 09:17:47,781-org.apache.ibatis.datasource.pooled.PooledDataSource-132 [main]DEBUGorg.apache.ibatis.datasource.pooled.PooledDataSource-PooledDataSource forcefully closed/removed all connections.
[lsjSso]2021-10-20 09:17:47,782-org.apache.ibatis.datasource.pooled.PooledDataSource-133 [main]DEBUGorg.apache.ibatis.datasource.pooled.PooledDataSource-PooledDataSource forcefully closed/removed all connections.
[lsjSso]2021-10-20 09:17:47,953-org.apache.ibatis.transaction.jdbc.JdbcTransaction-304 [main]DEBUGorg.apache.ibatis.transaction.jdbc.JdbcTransaction-Opening JDBC Connection
[lsjSso]2021-10-20 09:17:48,174-org.apache.ibatis.datasource.pooled.PooledDataSource-525 [main]DEBUGorg.apache.ibatis.datasource.pooled.PooledDataSource-Created connection 16503286.
[lsjSso]2021-10-20 09:17:48,174-org.apache.ibatis.transaction.jdbc.JdbcTransaction-525 [main]DEBUGorg.apache.ibatis.transaction.jdbc.JdbcTransaction-Setting autocommit to false on JDBC Connection [com.mysql.jdbc.JDBC4Connection@fbd1f6]
[lsjSso]2021-10-20 09:17:48,177-com.mybatis03.mapper.TeacherMapper.queryWithLazyGroupAndTeachers-528 [main]DEBUGcom.mybatis03.mapper.TeacherMapper.queryWithLazyGroupAndTeachers-==> Preparing: SELECT g.*,g.groupID AS groupno FROM teachergroup g WHERE g.groupid =?
[lsjSso]2021-10-20 09:17:48,211-com.mybatis03.mapper.TeacherMapper.queryWithLazyGroupAndTeachers-562 [main]DEBUGcom.mybatis03.mapper.TeacherMapper.queryWithLazyGroupAndTeachers-==> Parameters: 1(Integer)
[lsjSso]2021-10-20 09:17:48,257-com.mybatis03.mapper.TeacherMapper.queryWithLazyGroupAndTeachers-608 [main]DEBUGcom.mybatis03.mapper.TeacherMapper.queryWithLazyGroupAndTeachers-<== Total: 1
教研组编号:1,教研组名称:chinese
[lsjSso]2021-10-20 09:17:48,258-com.mybatis03.mapper.teacherGroupToTeacherMapper.queryGroupToTeacherByNO-609 [main]DEBUGcom.mybatis03.mapper.teacherGroupToTeacherMapper.queryGroupToTeacherByNO-==> Preparing: SELECT * FROM teacher WHERE groupno = ?
[lsjSso]2021-10-20 09:17一文搞定Mybatis 一对多延迟加载，并且子查询中与主表字段不对应