Question

我在项目中使用MyBatis作为持久层。

我在mySql db，paytransaction和paymenttype中有两个表，定义如下：

PayTransaction          PaymentType

Field                   Field
-------------           -------
id                  
payment_state       
creation_date       
update_date     
payment_type ----FK---->id
payment_id              description

因此，付款交易通过payment_type列（外键）关联了付款方式。

我的映射器的定义如下：

PayTransaction

<resultMap id="payTransactionPaymentTypeResultMap" type="com.XXX.payplatform.model.to.impl.TOPayTransaction" >
    <id     column="id"                     property="id"                   javaType="long"/>
    <result column="payment_state"          property="payment_state"        javaType="string"/>
    <result column="creation_date"          property="creation_date"        javaType="date"/>
    <result column="update_date"            property="update_date"          javaType="date"/>
    <result column="payment_id"             property="payment_id"           javaType="long"/>
    <association column="payment_type" property="paymentType" javaType="com.XXX.payplatform.model.to.impl.TOPaymentType" resultMap="com.XXX.payplatform.model.dao.interfaces.IDAOPaymentType.paymentTypeResultMap"/>
</resultMap>

PaymentType

<resultMap id="paymentTypeResultMap" type="com.XXX.payplatform.model.to.impl.TOPaymentType" >
    <id     column="id"                     property="id"                   javaType="long"/>
    <result column="description"            property="description"          javaType="string"/>
</resultMap>

SQL JOIN语句是：

<sql id="joinPayTransactionPaymentType">
    select paytransaction.id, paytransaction.payment_state, paytransaction.creation_date,paytransaction.update_date, paytransaction.payment_id, 
    paymenttype.id, paymenttype.description
    from paytransaction
    INNER JOIN paymenttype ON paymenttype.id = paytransaction.payment_type 
</sql>

问题来自payTransaction和paymenttype表中名为“id”的列。映射对象时，相同的值将转到ids字段，即如果paytransaction的id为39，则映射后java对象中的paymenttype的id在db中为3时也为39。

我尝试过写别名，比如：

<sql id="joinPayTransactionPaymentType">
    select paytransaction.id AS "paytransaction.id", paytransaction.payment_state as payment_state, paytransaction.creation_date as creation_date,paytransaction.update_date as update_date, paytransaction.payment_id as payment_id, 
    paymenttype.id AS "paymenttype.id", paymenttype.description as description
    from paytransaction
    INNER JOIN paymenttype ON paymenttype.id = paytransaction.payment_type 
</sql>

但没有结果。我认为唯一可行的解决方案是更改db中列的名称，例如“paymenttype_id”和“paytransaction_id”。

有没有解决方案或这是mybatis错误？

谢谢！

Answer 1

具有相同的属性名称对于MyBatis来说不是问题，只要您能够将明确的列（或列别名）映射到这些属性即可。为结果列指定别名时，也应为paymentTypeResultMap指定相同的列名。它应该工作。

<resultMap id="payTransactionPaymentTypeResultMap" type="com.XXX.payplatform.model.to.impl.TOPayTransaction" >
    <id     column="id"                     property="id"                   javaType="long"/>
    <result column="payment_state"          property="payment_state"        javaType="string"/>
    <result column="creation_date"          property="creation_date"        javaType="date"/>
    <result column="update_date"            property="update_date"          javaType="date"/>
    <result column="payment_id"             property="payment_id"           javaType="long"/>
    <association column="payment_type" property="paymentType" javaType="com.XXX.payplatform.model.to.impl.TOPaymentType" resultMap="com.XXX.payplatform.model.dao.interfaces.IDAOPaymentType.paymentTypeResultMap"/>
</resultMap>

...

<resultMap id="paymentTypeResultMap" type="com.XXX.payplatform.model.to.impl.TOPaymentType" >
    <id     column="paymenttype_id"                     property="id"                   javaType="long"/>
    <result column="description"            property="description"          javaType="string"/>
</resultMap>

...

<sql id="joinPayTransactionPaymentType">
    select paytransaction.id, paytransaction.payment_state as payment_state, paytransaction.creation_date as creation_date,paytransaction.update_date as update_date, paytransaction.payment_id as payment_id, 
    paymenttype.id AS paymenttype_id, paymenttype.description as description
    from paytransaction
    INNER JOIN paymenttype ON paymenttype.id = paytransaction.payment_type 
</sql>

mybatis列名冲突？

1 个答案: