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()+ "\t"+person.getName()+ "\t"+person.getAge()+ "\t"+passport.getSerial()+ "\t"+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()+ "\t"+passport.getExpiry()+ "\t"+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 >