MyBatis 一对一(OneToOne)__SELECT

1.创建SQL脚本：

CREATE TABLE t_person(
  id int(3) not null auto_increment,
  name varchar(20) default null,
  age int(3) default 0,
  primary key (id)
) charset="gb2312";

CREATE TABLE t_passport(
  id int(3),
  serial varchar(20) default NULL,
  expiry int(3) default NULL,
  PRIMARY KEY (id),
  CONSTRAINT fk_passport FOREIGN KEY (id) REFERENCES t_person(id)
)charset="gb2312";

--  t_passport主键Id 参照外键 t_person下的Id

2.创建实体类(POJO):

Person.java

package com.lixing.ibatis.entity.onetoone;

import java.io.Serializable;

public class Person implements Serializable{
  private static final long serialVersionUID = 4524251837950555570L;
  private int id;
  private String name;
  private int age;
  private Passport passport;  //Person指向Passport的引用
  
  public int getId() {
    return id;
  }
  public void setId(int id) {
    this.id = id;
  }
  public String getName() {
    return name;
  }
  public void setName(String name) {
    this.name = name;
  }
  public int getAge() {
    return age;
  }
  public void setAge(int age) {
    this.age = age;
  }
  public Passport getPassport() {
    return passport;
  }
  public void setPassport(Passport passport) {
    this.passport = passport;
  }
}

Passport.java

package com.lixing.ibatis.entity.onetoone;

public class Passport {
  private int id;
  private String serial;
  private int expiry;
  private Person person;  //Passport指向Person的引用
  
  public int getId() {
    return id;
  }
  public void setId(int id) {
    this.id = id;
  }
  public String getSerial() {
    return serial;
  }
  public void setSerial(String serial) {
    this.serial = serial;
  }
  public int getExpiry() {
    return expiry;
  }
  public void setExpiry(int expiry) {
    this.expiry = expiry;
  }
  public Person getPerson() {
    return person;
  }
  public void setPerson(Person person) {
    this.person = person;
  }  
}

3.创建Mapper接口:

PersonMapper.java

package com.lixing.ibatis.onetoone.mapper;

import com.lixing.ibatis.entity.onetoone.Person;

public interface PersonMapper {

  void insertPerson(Person person);
  Person getPerson(int id);
}

PassportMapper.java

package com.lixing.ibatis.onetoone.mapper;

import com.lixing.ibatis.entity.onetoone.Passport;

public interface PassportMapper {
  void insertPassport(Passport passport);
  Passport getPassport(int id);
}

4.创建Mapper映射XML文件：

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.lixing.ibatis.onetoone.mapper.PersonMapper">
  <parameterMap type="Person" id="parameterPersonMap">
    <parameter property="id"/>
    <parameter property="name"/>
    <parameter property="age"/>
  </parameterMap>
  
  <insert id="insertPerson"    parameterMap="parameterPersonMap">
    <selectKey    keyProperty="id" resultType="int" order="AFTER">
      SELECT LAST_INSERT_ID() AS ID
    </selectKey>
    INSERT INTO t_person(name,age)
    VALUES(#{name},#{age})
  </insert>  
  
  <resultMap type="Person" id="personMap">
    <result property="id" column="id"/>
    <result property="name" column="name"/>
    <result property="age" column="age"/>
    <association property="passport" column="id" javaType="Passport" select="com.lixing.ibatis.onetoone.mapper.PassportMapper.getPassport">
    </association>

<!-- property:指Person中指向Passport对象的实例名称  -->

<!--select:指执行级联查询-->
  </resultMap>  
  <select id="getPerson" resultMap="personMap" parameterType="int">
    SELECT * FROM t_person
    WHERE id=#{id}
  </select>
</mapper>    

PassportMapper.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.lixing.ibatis.onetoone.mapper.PassportMapper">
  <parameterMap type="Passport" id="passportMap">
    <parameter property="id"/>
    <parameter property="serial"/>
    <parameter property="expiry"/>    
  </parameterMap>
  
  <insert id="insertPassport" parameterMap="passportMap">
    INSERT INTO t_passport(id,serial,expiry)
    VALUES(?,?,?)
  </insert>    
  
  <resultMap type="Passport" id="passportMap">
    <result property="id" column="id"/>
    <result property="serial" column="serial"/>
    <result property="expiry" column="expiry"/>
    <association property="person" column="id" select="com.lixing.ibatis.onetoone.mapper.PersonMapper.getPerson">    
    </association>
  </resultMap>
  
  <select id="getPassport" resultMap="passportMap" parameterType="int">
    SELECT *
    FROM t_passport
    WHERE id=#{id}
  </select>        
</mapper>

5.创建测试类:

package com.lixing.ibatis.test;

import java.sql.SQLException;

import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.transaction.Transaction;
import org.apache.ibatis.transaction.TransactionFactory;
import org.apache.ibatis.transaction.jdbc.JdbcTransactionFactory;
import org.junit.After;
import org.junit.Before;
import org.junit.Ignore;
import org.junit.Test;

import com.lixing.ibatis.entity.onetoone.Passport;
import com.lixing.ibatis.entity.onetoone.Person;
import com.lixing.ibatis.onetoone.mapper.PassportMapper;
import com.lixing.ibatis.onetoone.mapper.PersonMapper;
import com.lixing.ibatis.util.MyBatisUtil;

public class PassportMapperTest {
  private SqlSessionFactory sqlSessionFactory = null;
  private SqlSession session = null;

  @Before
  public void before() {
    sqlSessionFactory = MyBatisUtil.getInstance();
    session = sqlSessionFactory.openSession();
  }

  @Test
  public void testInsertPerson() throws SQLException {
    Person person = new Person();
    person.setName("李新2");
    person.setAge(25);
    
    Passport passport = new Passport();
    
    passport.setSerial("Serial2");
    passport.setExpiry(22222);
    
    
    TransactionFactory transactionFactory = new JdbcTransactionFactory();
    Transaction tx = transactionFactory.newTransaction(session
        .getConnection(), false);    
    PersonMapper personMapper = session.getMapper(PersonMapper.class);
    PassportMapper passportMapper = session.getMapper(PassportMapper.class);
    try{
      personMapper.insertPerson(person);    
      passport.setId(person.getId());
      passportMapper.insertPassport(passport);
      tx.commit();
    }catch(Exception e){
      tx.rollback();
      e.printStackTrace();
    }finally{
      tx.close();
      System.out.println(person.getId());
    }
  }

  @Test
  public void testGetPerson(){
    PersonMapper personMapper=session.getMapper(PersonMapper.class);
    Person person=personMapper.getPerson(2);
    Passport passport=person.getPassport();
    System.out.println(person.getId()+" "+person.getName()+" "+person.getAge()+" "+passport.getSerial()+" "+passport.getExpiry());
    session.commit();
  }
  
  @Test
  public void testGetPassport(){
    PassportMapper passportMapper=session.getMapper(PassportMapper.class);
    Passport passport=passportMapper.getPassport(2);
    Person person=passport.getPerson();
    System.out.println(passport.getId()+" "+passport.getExpiry()+" "+person.getName());
  }
   

  @After
  public void after() {
     session.close();
  }
}

6.Mybatis配置文件:

mybatis-config.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>
  <settings>
    <!-- changes from the defaults for testing -->
    <setting name="cacheEnabled" value="false" />
    <setting name="useGeneratedKeys" value="true" />
    <setting name="defaultExecutorType" value="REUSE" />
  </settings>
  
  <typeAliases>
    <!---->
    <typeAlias alias="Passport" type="com.lixing.ibatis.entity.onetoone.Passport" />
    
    <typeAlias alias="Person" type="com.lixing.ibatis.entity.onetoone.Person"/>
  </typeAliases>

  <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://localhost:3306/test" />
        <property name="username" value="root" />
        <property name="password" value="7501857" />
      </dataSource>
    </environment>
  </environments>
  <mappers>
    <!---->
    <mapper resource="com/lixing/ibatis/onetoone/mapper/PassportMapper.xml" />
    
    <mapper resource="com/lixing/ibatis/onetoone/mapper/PersonMapper.xml" />
    
  </mappers>
</configuration>