MyBatis 一对一关联映射

怼烎@ 2022-05-15 05:34 281阅读 0赞

**示例【根据姓名查询身份证信息】**

**创建t\_person表**

![70][]

**创建t\_card表**

![70 1][]

**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"/>
      		
      		<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**

**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**

![70 2][]

[70]: /images/20220515/7ed595d5a6fc4c6b8528dd3050036473.png
[70 1]: /images/20220515/5cf05fc1d2284b1490660fb6cddcb47f.png
[70 2]: /images/20220515/07914b3a2a084a4b876048419469c55f.png