mybatis一對一关系保存

1.创建两个实体类，classes和teacher

package com.sq.entity;

public class Classes {

	private Integer id;
	private String name;
	private Teacher teacher;
	
	public Integer getId() {
		return id;
	}
	public void setId(Integer id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public Teacher getTeacher() {
		return teacher;
	}
	public void setTeacher(Teacher teacher) {
		this.teacher = teacher;
	}
	
	
	
}

package com.sq.entity;

public class Teacher {

	private Integer id;
	private String name;
	
	public Integer getId() {
		return id;
	}
	public void setId(Integer id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	
	
}

2.创建表

CREATE TABLE `classes` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `c_name` varchar(20) DEFAULT NULL,
  `t_id` int(11) DEFAULT NULL,
  PRIMARY KEY (`id`),
  KEY `545644` (`t_id`),
  CONSTRAINT `545644` FOREIGN KEY (`t_id`) REFERENCES `teacher` (`id`) ON DELETE NO ACTION ON UPDATE NO ACTION
) ENGINE=InnoDB AUTO_INCREMENT=10 DEFAULT CHARSET=utf8;

CREATE TABLE `teacher` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `t_name` varchar(20) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=utf8;

3.创建关系映射

ClassesMapper.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org/DTD Mapper 3.0" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.sq.dao.ClassMapper">
	<resultMap type="Teacher" id="teacherMap">
		<id property="id" column="id" javaType="int"/>
		<result property="name" column="t_name"/>
	</resultMap>
	
	<resultMap type="Classes" id="classMap">
		<id property="id" column="id" javaType="int"/>
		<result property="name" column="c_name"/>
		<association property="teacher" resultMap="teacherMap" javaType="Teacher" column="t_id"></association>
	</resultMap>
	
	<insert id="insertClass" useGeneratedKeys="true" keyProperty="id" parameterType="Classes">
		<!-- <selectKey    keyProperty="id" resultType="int" order="AFTER"> 
	      SELECT LAST_INSERT_ID() AS ID 
	    </selectKey>  可有可无-->
		insert into classes(c_name,t_id) values(#{name},#{teacher.id}) 
	</insert>
</mapper>

TeacherMapper.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org/DTD Mapper 3.0" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.sq.dao.TeacherMapper">
	<insert id="insertTeacher" useGeneratedKeys="true" keyProperty="id" parameterType="Teacher">
		insert into teacher(t_name) values(#{name}) 
	</insert>
</mapper>

4测试类

public class Test1 {
private static SqlSessionFactory sqlSessionFactory;
public static void main(String[] args) {
// Mybatis 配置文件
String resource = "mybatis.cfg.xml";
// 得到配置文件流
InputStream inputStream = null;
try {
inputStream = Resources.getResourceAsStream(resource);
} catch (IOException e) {
e.printStackTrace();
}
// 创建会话工厂，传入 MyBatis 的配置文件信息
sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
SqlSession session = sqlSessionFactory.openSession();
Teacher teacher = new Teacher();
teacher.setName("Mr.zhang");
teacher.setId(1);
Classes classes = new Classes();
classes.setName("三年级一班");
ClassMapper classMap = session.getMapper(ClassMapper.class);
TeacherMapper teacherMap = session.getMapper(TeacherMapper.class);
try {
teacherMap.insertTeacher(teacher);//先保存没有外键的一方
classes.setTeacher(teacher);//再set给有外键的一方
classMap.insertClass(classes);//保存有外键的一方
session.commit();
} catch (Exception e) {
e.printStackTrace();
}
}