MyBatis的discriminator鉴别器根据字段值实现Java中的多态

    <select id="getModelById" resultMap="modelTypeMap">

        SELECT id as id,

        model_id AS modelId,

        model_type AS modelType,

        created_by AS createdBy,

        model_name AS modelName,

        model_def AS modelDef,

        start_date AS startDate,

        end_date AS endDate,

        FROM

        <include refid="user_defined_4a_model"/>

        WHERE model_id=#{modelId}

    </select>

    <resultMap id="modelTypeMap" type="com.javartisan.BaseModel">

        <discriminator javaType="java.lang.Integer" column="modelType">

            <case value="1" resultType="com.javartisan.Model1"/>

            <case value="2" resultType="com.javartisan.Model2"/>

        </discriminator>

    </resultMap>