数据库显示：
employee表（通过外键，建立与department表之间的关系）
department表
（
部分笔记来源于网上课堂）
具体实现：
文件总体目录结构
mybatis.xml
<?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>
<properties resource="db.properties"></properties>
<typeAliases>
<typeAlias type="many2one.domain.department" alias="department"></typeAlias>
<typeAlias type="many2one.domain.employee" alias="employee"></typeAlias>
</typeAliases>
<environments default="default">
<environment id="default">
<transactionManager type="JDBC"></transactionManager>
<dataSource type="POOLED">
<property name="driver" value="${db.driverClassName}"></property>
<property name="url" value="${db.url}"></property>
<property name="username" value="${db.username}"></property>
<property name="password" value="${db.password}"></property>
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="many2one/domain/departmapper.xml"></mapper>
<mapper resource="many2one/domain/employeemapper.xml"></mapper>
</mappers>
</configuration>
db.properties
db.driverClassName=com.mysql.jdbc.Driver
db.url=jdbc:mysql://localhost:3306/mybatis
db.username=root
db.password=123456
log4j.properties
# Global logging configuration
log4j.rootLogger=ERROR, stdout
# MyBatis logging configuration...
log4j.logger.many2one.domain=TRACE
# Console output...
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n
departmapper.xml
<?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="many2one.domain.departmapper">
<insert id="deptsave" parameterType="department" keyProperty="id" keyColumn="id" useGeneratedKeys="true">
INSERT INTO department(name)VALUES(#{name})
</insert>
<select id="deptsearch" parameterType="long" resultType="department">
SELECT *FROM department WHERE id=#{id}
</select>
</mapper>
employeemapper.xml
<?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="many2one.domain.employeemapper">
<resultMap id="base" type="employee">
<id column="id" property="id"></id>
<result column="name" property="name"></result>
<association property="dept" column="dept_id" javaType="department" select="many2one.domain.departmapper.deptsearch"></association>//关联查询使用association，其中
</resultMap>
<insert id="save" parameterType="employee" keyColumn="id" keyProperty="id" useGeneratedKeys="true">
INSERT INTO employee(name,dept_id)VALUES(#{name},#{dept.id})
</insert>
<select id="search" parameterType="long" resultMap="base">
SELECT *FROM employee WHERE id=#{id}
</select>
</mapper>
departmapper接口
package many2one.domain;
public interface departmapper {
void deptsave(department d);
department deptsearch(Long id);
}
employeemapper接口
package many2one.domain;
public interface employeemapper {
void save(employee e);
employee search(Long id);
}
mybatisutils工具类
package many2one.utils;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import java.io.IOException;
public class mybatisutils {
private SqlSessionFactory sf;
private static mybatisutils instance=new mybatisutils();
public mybatisutils(){
try {
sf=new SqlSessionFactoryBuilder().build(Resources.getResourceAsStream("mybatis.xml"));
} catch (IOException e) {
e.printStackTrace();
}
}
public static SqlSession opensession(){
return instance.sf.openSession();
}
}
employee类
package many2one.domain;
public class employee {
private Long id;
private String name;
private department dept;
public employee(){} //不可缺少，否则报初始化错误，详细链接参考https://blog.csdn.net/sunrise_zhu/article/details/53309767
public employee(String name, department dept) {
this.name = name;
this.dept = dept;
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public department getDept() {
return dept;
}
public void setDept(department dept) {
this.dept = dept;
}
@Override
public String toString() {
return "employee{" +
"id=" + id +
", name='" + name + '\'' +
'}';
}
}
department类
package many2one.domain;
public class department {
private Long id;
private String name;
public department(){} //不可缺少，否则报初始化错误
public department(String name) {
this.name = name;
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public String toString() {
return "department{" +
"id=" + id +
", name='" + name + '\'' +
'}';
}
}
test测试方法类
package many2one.domain;
import com.sun.scenario.effect.impl.sw.sse.SSEBlend_SRC_OUTPeer;
import many2one.utils.mybatisutils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;
public class test {
@Test
public void test(){
SqlSession session= mybatisutils.opensession();
departmapper deptmap=session.getMapper(departmapper.class);
employeemapper emmap=session.getMapper(employeemapper.class);
department d=new department("部门1");
employee e=new employee("员工1",d);
deptmap.deptsave(d);
emmap.save(e);
session.close();
}
@Test
public void testsearch(){
SqlSession session= mybatisutils.opensession();
departmapper deptmap=session.getMapper(departmapper.class);
employeemapper emmap=session.getMapper(employeemapper.class);
department d=deptmap.deptsearch(7L);
employee e=emmap.search(2L);
System.out.println(d+" "+e);
session.close();
}
}
测试结果：
