1.下面是我的idea的目录结构:
mybatis01.jpg
2.下面是com.it.pojo的代码:
package com.it.pojo;
public class User {
private int uid;
private String name;
private String pass;
private String phone;
//setter和getter,toString省略
}
public class Types {
private String tid;
private String name;
//setter和getter,toString省略
}
public class Product {
private String pid;
private String name;
private String img;
private double price;
private Types t;
//setter和getter,toString省略
}
public class Detail {
private String did;
private int count;
private Product p;
//setter和getter,toString省略
}
import java.util.List;
public class Order {
private String oid;
private double price;
private String addr;
private String payType;
private User u;
private List<Detail> Details;
//setter和getter,toString省略
}
3.下面是mybatis的核心文件配置
<?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>
<setting name="cacheEnabled" value="true" />
<setting name="useGeneratedKeys" value="true" />
<setting name="defaultExecutorType" value="REUSE" />
<setting name="logImpl" value="STDOUT_LOGGING" />
</settings>
<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://127.0.0.1:3306/mall"/>
<property name="username" value="root"/>
<property name="password" value="tiger"/>
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="com.it.mapper/OrderMapper.xml"/>
<mapper resource="com.it.mapper/UserMapper.xml"/>
<mapper resource="com.it.mapper/DetailMapper.xml"/>
<mapper resource="com.it.mapper/ProductMapper.xml"/>
<mapper resource="com.it.mapper/TypesMapper.xml"/>
</mappers>
</configuration>
4.下面是各个mapper文件的配置
下面是UserMapper.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.it.pojo.UserMapper">
<select id="selectUser" resultType="com.it.pojo.User">
select * from users where uid=#{uid};
</select>
</mapper>
下面是TypesMapper.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.it.pojo.TypesMapper">
<select id="selectTypesByID" resultType="com.it.pojo.Types">
select * from types where tid=#{tid};
</select>
</mapper>
下面是ProductMapper.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.it.pojo.ProductMapper">
<select id="selectProductById" resultMap="productMap">
select * from products where pid=#{pid};
</select>
<resultMap id="productMap" type="com.it.pojo.Product">
<id column="pid" property="pid"></id>
<result property="name" column="name"></result>
<result column="img" property="img"></result>
<result column="price" property="price"></result>
<association property="t" column="tid" select="com.it.pojo.TypesMapper.selectTypesByID"></association>
</resultMap>
</mapper>
下面是DetailMapper.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.it.pojo.DetailMapper">
<select id="getDetailsByOid" resultMap="detailMap">
select * from details where oid=#{oid};
</select>
<resultMap id="detailMap" type="com.it.pojo.Detail">
<id column="did" property="did"></id>
<result property="count" column="count"></result>
<association property="p" column="pid" select="com.it.pojo.ProductMapper.selectProductById"></association>
</resultMap>
</mapper>
下面是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.it.pojo.OrderMapper">
<select id="getOrderById" resultMap="orderMap">
select * from orders where oid=#{oid};
</select>
<resultMap id="orderMap" type="com.it.pojo.Order">
<id property="oid" column="oid"></id>
<result property="price" column="price"></result>
<result property="addr" column="addr"></result>
<result property="payType" column="payType"></result>
<!--
association关联,只要是"对一"的关系都可以使用association,代表关联
property代表Order类中的属性名u
column代表Orders表与Users表之间的关联字段
select代表要使用该查询完成两表的联合查询得出user对象
-->
<association property="u" column="uid" select="com.it.pojo.UserMapper.selectUser"></association>
<collection property="Details" column="oid" select="com.it.pojo.DetailMapper.getDetailsByOid"></collection>
</resultMap>
</mapper>
5.下面是测试代码以及测试结果展示
import com.it.pojo.Order;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import java.io.IOException;
public class TestOrders {
private SqlSessionFactory sf = null;
private SqlSession session = null;
@Before
public void setUp(){
try {
sf = new SqlSessionFactoryBuilder().build(Resources.getResourceAsStream("mybatis.xml"));
session = sf.openSession();
} catch (IOException e) {
e.printStackTrace();
}
}
@After
public void tearDown(){
if(session != null){
session.close();
session = null;
}
}
@Test
public void testGetOrderByOid(){
Order order = session.selectOne("com.it.pojo.OrderMapper.getOrderById", "7891834e633011eab732005056c00001");
System.out.println(order);
}
}
下面是测试结果展示:
Logging initialized using 'class org.apache.ibatis.logging.stdout.StdOutImpl' adapter.
PooledDataSource forcefully closed/removed all connections.
PooledDataSource forcefully closed/removed all connections.
PooledDataSource forcefully closed/removed all connections.
PooledDataSource forcefully closed/removed all connections.
Opening JDBC Connection
Created connection 1684890795.
Setting autocommit to false on JDBC Connection [com.mysql.jdbc.JDBC4Connection@646d64ab]
==> Preparing: select * from orders where oid=?;
==> Parameters: 7891834e633011eab732005056c00001(String)
<== Columns: oid, price, addr, payType, uid
<== Row: 7891834e633011eab732005056c00001, 30998, beijingxisanqi, zhibubao, 1
====> Preparing: select * from users where uid=?;
====> Parameters: 1(Integer)
<==== Columns: uid, name, pass, phone
<==== Row: 1, wukong, 888888, 13333333333
<==== Total: 1
====> Preparing: select * from details where oid=?;
====> Parameters: 7891834e633011eab732005056c00001(String)
<==== Columns: did, count, pid, oid
<==== Row: 61f4c1d3633211eab732005056c00001, 1, b8591f77633111eab732005056c00001, 7891834e633011eab732005056c00001
======> Preparing: select * from products where pid=?;
======> Parameters: b8591f77633111eab732005056c00001(String)
<====== Columns: pid, name, img, price, tid
<====== Row: b8591f77633111eab732005056c00001, mac.pro, mac.jpg, 21999, 007ca8fb632f11eab732005056c00001
========> Preparing: select * from types where tid=?;
========> Parameters: 007ca8fb632f11eab732005056c00001(String)
<======== Columns: tid, name
<======== Row: 007ca8fb632f11eab732005056c00001, digit
<======== Total: 1
<====== Total: 1
<==== Row: 61f4c3b1633211eab732005056c00001, 1, b8592172633111eab732005056c00001, 7891834e633011eab732005056c00001
======> Parameters: b8592172633111eab732005056c00001(String)
<====== Columns: pid, name, img, price, tid
<====== Row: b8592172633111eab732005056c00001, iphone, iphone.jpg, 9999, 007ca8fb632f11eab732005056c00001
<====== Total: 1
<==== Row: 61f4c400633211eab732005056c00001, 1, b85921bc633111eab732005056c00001, 7891834e633011eab732005056c00001
======> Parameters: b85921bc633111eab732005056c00001(String)
<====== Columns: pid, name, img, price, tid
<====== Row: b85921bc633111eab732005056c00001, yagao, yagao.jpg, 50, 007ca7cd632f11eab732005056c00001
========> Parameters: 007ca7cd632f11eab732005056c00001(String)
<======== Columns: tid, name
<======== Row: 007ca7cd632f11eab732005056c00001, house
<======== Total: 1
<====== Total: 1
<==== Total: 3
<== Total: 1
Order{oid='7891834e633011eab732005056c00001', price=30998.0, addr='beijingxisanqi', payType='zhibubao', u=user{uid=1, name='wukong', pass='888888', phone='13333333333'}, Details=[Detail{did='61f4c1d3633211eab732005056c00001', count=1, p=Product{pid='b8591f77633111eab732005056c00001', name='mac.pro', img='mac.jpg', price=21999.0, t=Types{tid='007ca8fb632f11eab732005056c00001', name='digit'}}}, Detail{did='61f4c3b1633211eab732005056c00001', count=1, p=Product{pid='b8592172633111eab732005056c00001', name='iphone', img='iphone.jpg', price=9999.0, t=Types{tid='007ca8fb632f11eab732005056c00001', name='digit'}}}, Detail{did='61f4c400633211eab732005056c00001', count=1, p=Product{pid='b85921bc633111eab732005056c00001', name='yagao', img='yagao.jpg', price=50.0, t=Types{tid='007ca7cd632f11eab732005056c00001', name='house'}}}]}
Resetting autocommit to true on JDBC Connection [com.mysql.jdbc.JDBC4Connection@646d64ab]
Closing JDBC Connection [com.mysql.jdbc.JDBC4Connection@646d64ab]
Returned connection 1684890795 to pool.
