Mybatis 一对多(OneToOne)关系映射

关于MyBatis一对多的设置如下:

1.创建数据库脚本

CREATE TABLE t_customer(
  id int(10) not null auto_increment,
  address varchar(120),
  postcode varchar(6),
  sex varchar(2),
  cname varchar(24),
  primary key(id)
)charset="GB2312";

CREATE TABLE t_orders(
  id int(10) not null auto_increment,
  code varchar(24),
  customer_id int(3) not null,
  primary key(id)
)charset="GB2312";

ALTER TABLE t_orders
ADD CONSTRAINT orders_customer_fk FOREIGN KEY (customer_id) REFERENCES t_customer(id)

-- t_orders.customer_id 参照 t_customer.id

 

2.创建实体类(POJO)

Customer.java

package com.lixing.ibatis.entity.onetomany;

import java.io.Serializable;
import java.util.List;

public class Customer implements Serializable{
  private static final long serialVersionUID = 451949797460417653L;
  private int id;
  private String address;
  private String postcode;
  private String sex;
  private String cname;
  private List<Orders> orders;   //一个Customer 对应N多个Orders

  public int getId() {
    return id;
  }
  public void setId(int id) {
    this.id = id;
  }
  public String getAddress() {
    return address;
  }
  public void setAddress(String address) {
    this.address = address;
  }
  public String getPostcode() {
    return postcode;
  }
  public void setPostcode(String postcode) {
    this.postcode = postcode;
  }
  public String getSex() {
    return sex;
  }
  public void setSex(String sex) {
    this.sex = sex;
  }
  public String getCname() {
    return cname;
  }
  public void setCname(String cname) {
    this.cname = cname;
  }
  public List<Orders> getOrders() {
    return orders;
  }
  public void setOrders(List<Orders> orders) {
    this.orders = orders;
  }
}

 

Orders.java

package com.lixing.ibatis.entity.onetomany;

import java.io.Serializable;

public class Orders implements Serializable {
  private static final long serialVersionUID = 8215977396669780567L;
  private int id;
  private String code;
  private int customerId;
  private Customer customer;  //多个Orders对应一个Customer
    
  public int getId() {
    return id;
  }

  public void setId(int id) {
    this.id = id;
  }

  public String getCode() {
    return code;
  }

  public void setCode(String code) {
    this.code = code;
  }

  public int getCustomerId() {
    return customerId;
  }

  public void setCustomerId(int customerId) {
    this.customerId = customerId;
  }

  public Customer getCustomer() {
    return customer;
  }

  public void setCustomer(Customer customer) {
    this.customer = customer;
  }
}

 

3.创建Mapper映射接口

CustomerMapper.java

package com.lixing.ibatis.onetomany.mapper;

import com.lixing.ibatis.entity.onetomany.Customer;

public interface CustomerMapper {
  void insertCustomer(Customer customer);
  Customer getCustomer(int id);
}

 

OrdersMapper.java

package com.lixing.ibatis.onetomany.mapper;

import java.util.List;

import com.lixing.ibatis.entity.onetomany.Orders;

public interface OrdersMapper {
  void insertOrders(Orders orders);
  List<Orders> getOrders(int id);    //根据id
  List<Orders> getOrdersById(int customerId);   //根据customerId获得N多个对象
}

 

4.创建Mapper XML配置文件

CustomerMapper.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.onetomany.mapper.CustomerMapper">
  <parameterMap type="Customer" id="parameterCustomerMap">
    <parameter property="id"/>
    <parameter property="address"/>
    <parameter property="postcode"/>
    <parameter property="sex"/>
    <parameter property="cname"/>    
  </parameterMap>
    
  <insert id="insertCustomer" parameterMap="parameterCustomerMap">
    <selectKey    keyProperty="id" resultType="int" order="AFTER">
      SELECT @@IDENTITY AS ID
    </selectKey>
    INSERT INTO t_customer(address,postcode,sex,cname)
    VALUES(#{address},#{postcode},#{sex},#{cname})
  </insert>        
    
  <resultMap type="Customer" id="resultCustomerMap">
    <result property="id" column="id"/>
    <result property="address" column="address"/>
    <result property="postcode" column="postcode"/>
    <result property="sex" column="sex"/>
    <result property="cname" column="cname"/>
    <collection property="orders" column="id" select="com.lixing.ibatis.onetomany.mapper.OrdersMapper.getOrdersById"/>
  </resultMap>
    
  <select id="getCustomer" resultMap="resultCustomerMap" parameterType="int">
    SELECT *
    FROM t_customer
    WHERE id=#{id}
  </select>        
</mapper>

OrderMapper.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.onetomany.mapper.OrdersMapper">
  <parameterMap type="Orders" id="parameterOrdersMap">
    <parameter property="id"/>
    <parameter property="code"/>
    <parameter property="customerId"/>
  </parameterMap>
    
  <insert id="insertOrders"    parameterMap="parameterOrdersMap">
    <selectKey    keyProperty="id" resultType="int" order="AFTER">
      SELECT LAST_INSERT_ID() AS ID
    </selectKey>
    INSERT INTO t_orders(code,customer_id)
    VALUES(#{code},#{customerId})
  </insert>    
    
  <resultMap type="Orders" id="ordersMap">
    <result property="id" column="id"/>
    <result property="code" column="name"/>
    <result property="customerId" column="customer_id"/>
    <association property="customer" javaType="Customer" column="customer_id" select="com.lixing.ibatis.onetomany.mapper.CustomerMapper.getCustomer"/>
  </resultMap>    
  <select id="getOrders" resultMap="ordersMap" parameterType="int">
    SELECT * FROM t_orders
    WHERE id=#{id}
  </select>
    
  <select id="getOrdersById" resultMap="ordersMap" parameterType="int">
    SELECT * FROM t_orders
    WHERE customer_id=#{customer_id}
  </select>
    
</mapper>    

 

5.mybatis-config.xml 文件

<?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 type="com.lixing.ibatis.entity.onetomany.Customer" alias="Customer"/>
    <typeAlias type="com.lixing.ibatis.entity.onetomany.Orders" alias="Orders"/>
    
  </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/onetomany/mapper/CustomerMapper.xml"/>
    <mapper resource="com/lixing/ibatis/onetomany/mapper/OrdersMapper.xml"/>
  </mappers>
</configuration>

 

6.创建测试类

package com.lixing.ibatis.test;

import java.util.Iterator;
import java.util.List;

import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import com.lixing.ibatis.entity.onetomany.Customer;
import com.lixing.ibatis.entity.onetomany.Orders;
import com.lixing.ibatis.onetomany.mapper.CustomerMapper;
import com.lixing.ibatis.onetomany.mapper.OrdersMapper;
import com.lixing.ibatis.util.MyBatisUtil;


public class OrdersMapperTest {
  private SqlSessionFactory sqlSessionFactory=null;
  private SqlSession session=null;
    
  @Before
  public void before(){
    sqlSessionFactory=MyBatisUtil.getInstance();
    session=sqlSessionFactory.openSession();
  }
    
  @Test
  public void testInsertOrders(){
    Orders orders=new Orders();
    orders.setCode("code__1");
    orders.setCustomerId(1);
    
    OrdersMapper ordersMapper=session.getMapper(OrdersMapper.class);
    ordersMapper.insertOrders(orders);
    session.commit();    
  }
    
  @Test
  public void testInsertCustomerOneToMany(){
    Customer customer=new Customer();
    customer.setCname("Lixing5");
    customer.setPostcode("518105");
    customer.setSex("男");
    customer.setAddress("广东省深圳市5");
    
    CustomerMapper customerMapper=session.getMapper(CustomerMapper.class);
    customerMapper.insertCustomer(customer);
    System.out.println(customer.getId());
    
    Orders orders1=new Orders();
    orders1.setCode("code__5_1");
    orders1.setCustomerId(customer.getId());
    
    Orders orders2=new Orders();
    orders2.setCode("code__5_2");
    orders2.setCustomerId(customer.getId());
    
    Orders orders3=new Orders();
    orders3.setCode("code__5_3");
    orders3.setCustomerId(customer.getId());
    
    OrdersMapper ordersMapper=session.getMapper(OrdersMapper.class);
    ordersMapper.insertOrders(orders1);
    ordersMapper.insertOrders(orders2);
    ordersMapper.insertOrders(orders3);
    
    session.commit();    
  } 
    
     
  @Test
  public void testGetOrdersManyToOne(){
    OrdersMapper ordersMapper=session.getMapper(OrdersMapper.class);
    List<Orders> list=ordersMapper.getOrdersById(5);
    for(int i=0;i<list.size();i++){
      Orders orders=list.get(i);
      Customer customer=orders.getCustomer();
      System.out.println(orders.getId()+"\t"+orders.getCode()+"\t"+orders.getCustomerId());
      System.out.println("\t \t--:"+customer.getId()+"\t"+customer.getCname());
    }    
    session.commit();
  }
    
    
  @Test
  public void testGetCustomerOneToMany(){
    CustomerMapper customerMapper=session.getMapper(CustomerMapper.class);
    Customer customer=customerMapper.getCustomer(5);
    List<Orders> orders=customer.getOrders();
    System.out.println(customer.getId()+"\t"+customer.getCname()+"\t"+customer.getPostcode()+"\t"+customer.getAddress());
    for(int i=0;i<orders.size();i++){
      Orders order=orders.get(i);
      System.out.println("\t \t --:"+order.getId()+"\t"+order.getCode()+"\t"+order.getCustomerId());
    }
    session.commit();
  }
    
  @After
  public void after(){
    session.close();
  }
}