Mybatis的XML映射文件的继承问题

2018-08-13 07:37:59来源：博客园阅读 ()

1.首先dao层mapper.java需要继承原来的接口

　　原dao层接口

public interface TagMapper {
    /**
     * This method was generated by MyBatis Generator.
     * This method corresponds to the database table t_tag
     *
     * @mbg.generated
     */
    long countByExample(TagExample example);

    /**
     * This method was generated by MyBatis Generator.
     * This method corresponds to the database table t_tag
     *
     * @mbg.generated
     */
    int deleteByExample(TagExample example);
}

　　扩展后的dao层接口

public interface TagExtendMapper extends TagMapper {
    ...
}

2.继承原始mapper.xml的结果映射

　　原始mapper.xml的结果映射

<mapper namespace="com.xxx.dao.mapper.TagMapper">
  <resultMap id="BaseResultMap" type="com.xxx.dao.Tag">
    <!--
      WARNING - @mbg.generated
      This element is automatically generated by MyBatis Generator, do not modify.
    -->
    <id column="id" jdbcType="CHAR" property="id" />
    <result column="tag_name" jdbcType="VARCHAR" property="tagName" />
    <result column="tag_alias" jdbcType="VARCHAR" property="tagAlias" />
  </resultMap>
</mapper>

　　扩展mapper.xml的结果映射

<mapper namespace="com.xxx.dao.TagExtendMapper">
    <select id="xxxxx" resultMap="com.xxx.dao.mapper.TagMapper.BaseResultMap"> <!-- 这里时原始命名空间加上结果集id -->
    </select>
</mapper>

　　或者是

<mapper namespace="com.xxx.dao.TagExtendMapper">
   <resultMap id="ExtBaseResultMap" type="com.xxx.dao.Tag" extend="com.xxx.dao.mapper.TagMapper.BaseResultMap">
       ...
  </resultMap>
</mapper>