MyBatis 集成 - CUBA 框架开发者手册

3.9.11. MyBatis 集成

MyBatis 框架，与 ORM 本地查询或QueryRunner相比，提供了更广泛的执行 SQL 和将查询结果映射到对象的功能。

按照下面的步骤在 CUBA 项目中集成 MyBatis。

在 core 模块的根 java 包创建处理 UUID 类型的类。

import com.haulmont.cuba.core.global.UuidProvider;
import org.apache.ibatis.type.JdbcType;
import org.apache.ibatis.type.TypeHandler;

import java.sql.*;

public class UUIDTypeHandler implements TypeHandler {

    @Override
    public void setParameter(PreparedStatement ps, int i, Object parameter, JdbcType jdbcType) throws SQLException {
        ps.setObject(i, parameter, Types.OTHER);
    }

    @Override
    public Object getResult(ResultSet rs, String columnName) throws SQLException {
        String val = rs.getString(columnName);
        if (val != null) {
            return UuidProvider.fromString(val);
        } else {
            return null;
        }
    }

    @Override
    public Object getResult(ResultSet rs, int columnIndex) throws SQLException {
        String val = rs.getString(columnIndex);
        if (val != null) {
            return UuidProvider.fromString(val);
        } else {
            return null;
        }
    }

    @Override
    public Object getResult(CallableStatement cs, int columnIndex) throws SQLException {
        String val = cs.getString(columnIndex);
        if (val != null) {
            return UuidProvider.fromString(val);
        } else {
            return null;
        }
    }
}

在 core 模块的 spring.xml 文件所在目录创建 mybatis.xml 配置文件，在文件内正确引用 UUIDTypeHandler：

<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <settings>
        <setting name="lazyLoadingEnabled" value="false"/>
    </settings>
    <typeHandlers>
        <typeHandler javaType="java.util.UUID"
                     handler="com.company.demo.core.UUIDTypeHandler"/>
    </typeHandlers>
</configuration>

将下面的 bean 都添加到 spring.xml 文件以便在项目中使用 MyBatis：

<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
    <property name="dataSource" ref="cubaDataSource"/>
    <property name="configLocation" value="com/company/demo/mybatis.xml"/>
    <property name="mapperLocations" value="com/company/demo/core/sqlmap/*.xml"/>
</bean>

<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
    <property name="basePackage" value="com/company/demo.core.dao"/>
    <property name="sqlSessionFactory" ref="sqlSessionFactory"/>
</bean>

<bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate">
    <constructor-arg index="0" ref="sqlSessionFactory" />
</bean>

sqlSessionFactory bean 包含了指向 mybatis.xml 的引用。

MapperLocations 参数定义了 mapperLocations 映射文件的路径（根据 Spring 中 ResourceLoader 接口的资源解析规则）。

最后，在 build.gradle 中的 core 模块添加 MyBatis 的依赖：

compile('org.mybatis:mybatis:3.2.8')
compile('org.mybatis:mybatis-spring:1.2.5')

下面是一个映射文件的示例，用于加载 订单(Order) 的实例以及相关的 客户(Customer) 和 订单商品(order item) 集合：

<?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.sample.sales">

    <select id="selectOrder" resultMap="orderResultMap">
        select
        o.ID as order_id,
        o.DATE as order_date,
        o.AMOUNT as order_amount,
        c.ID as customer_id,
        c.NAME as customer_name,
        c.EMAIL as customer_email,
        i.ID as item_id,
        i.QUANTITY as item_quantity,
        p.ID as product_id,
        p.NAME as product_name
        from
        SALES_ORDER o
        left join SALES_CUSTOMER c on c.ID = o.CUSTOMER_ID
        left join SALES_ITEM i on i.ORDER_ID = o.id and i.DELETE_TS is null
        left join SALES_PRODUCT p on p.ID = i.PRODUCT_ID
        where
        c.id = #{id}
    </select>

    <resultMap id="orderResultMap" type="com.sample.sales.entity.Order">
        <id property="id" column="order_id"/>
        <result property="date" column="order_date"/>
        <result property="amount" column="order_amount"/>

        <association property="customer" column="customer_id" javaType="com.sample.sales.entity.Customer">
            <id property="id" column="customer_id"/>
            <result property="name" column="customer_name"/>
            <result property="email" column="customer_email"/>
        </association>

        <collection property="items" ofType="com.sample.sales.entity.Item">
            <id property="id" column="item_id"/>
            <result property="quantity" column="item_quantity"/>
            <association property="product" column="product_id" javaType="com.sample.sales.entity.Product">
                <id property="id" column="product_id"/>
                <result property="name" column="product_name"/>
            </association>
        </collection>
    </resultMap>

</mapper>

以下代码可用于获取上面示例中的查询结果：

try (Transaction tx = persistence.createTransaction()) {
    SqlSession sqlSession = AppBeans.get("sqlSession");
    Order order = (Order) sqlSession.selectOne("com.sample.sales.selectOrder", orderId);
    tx.commit();