MyBatis 一对一关联映射

示例【根据姓名查询身份证信息】

创建t_person表

创建t_card表

创建Person

package com.po;

public class Person {
	private Integer pId;
	private String pName;
	private String sex;
	private Card card;
	public Integer getpId() {
		return pId;
	}
	public void setpId(Integer pId) {
		this.pId = pId;
	}
	public String getpName() {
		return pName;
	}
	public void setpName(String pName) {
		this.pName = pName;
	}
	public String getSex() {
		return sex;
	}
	public void setSex(String sex) {
		this.sex = sex;
	}
	public Card getCard() {
		return card;
	}
	public void setCard(Card card) {
		this.card = card;
	}
	@Override
	public String toString() {
		return "Person [pId=" + pId + ", pName=" + pName + ", sex=" + sex + ", card=" + card + "]";
	}
}

创建Card

package com.po;

public class Card {
	private Integer cId;
	private String code;
	public Integer getcId() {
		return cId;
	}
	public void setcId(Integer cId) {
		this.cId = cId;
	}
	public String getCode() {
		return code;
	}
	public void setCode(String code) {
		this.code = code;
	}
	@Override
	public String toString() {
		return "Card [cId=" + cId + ", code=" + code + "]";
	}
}

创建PersonMapper.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="com.mapper.PersonMapper">
  	<resultMap type="com.po.Person" id="PersonWithCard">
  		<id property="pId" column="pId"/>
  		<result property="pName" column="pName"/>
  		<result property="sex" column="sex"/>
  		<!-- 使用select属性引入另外一条sql语句 -->
  		<association property="card" javaType="com.po.Card">
  			<id property="cId" column="cId"/>
  			<result property="code" column="code"/>
  		</association>
  	</resultMap>
  	<select id="findPersonByCid" parameterType="Integer" resultMap="PersonWithCard">
  		select * from t_person p,t_card c where p.cId=c.cId and p.pId=#{pId}
  	</select>
  </mapper>

配置mybatis-config.xml

<mappers>
		<mapper resource="com/mapper/PersonMapper.xml"/>		
</mappers>

创建PersonDao

package com.dao;

import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import com.factory.SessionFactory;
import com.po.Person;

public class PersonDao {
	private SqlSession session=SessionFactory.getSqlSession();
	@Test
	public void findPersonById() {
		Person person=session.selectOne("com.mapper.PersonMapper.findPersonByCid", 1);
		System.out.println(person);
	}
}

执行findPersonById()方法