mybatis多层嵌套 xml记录一下

 

@Data
public final class World implements Serializable {
    private static final long serialVersionUID = 1L;
    private int id = 0;
    private name = null;
}

@Data
public final class Province implements Serializable {
    private static final long serialVersionUID = 1L;
    private int id = 0;
    private int countryId = 0;
    private name = null;
}

@Data
public final class City implements Serializable {
    private static final long serialVersionUID = 1L;
    private int id = 0;
    private int proId = 0;
    private name = null;
}

 <resultMap id="countryMap" type="com.main.entity.World">
       <id column="map_id"/>
       <result column="name"/>
       <collection property="provinceList" ofType="com.main.entity.Province" select="findProvince" column="{id=mapId}"/>
</resultMap>

<resultMap id="provinceList" type="com.main.entity.Province">
       <id column="pro_id"/>
       <result column="name"/>
       <collection property="cityList" ofType="com.main.entity.City" select="findCity" column="{id=proId}" />
</resultMap>

<resultMap id="cityList" type="com.main.entity.City">
       <id column="city_id"/>
       <result column="name"/>
</resultMap>

<select id = "findChina" resultType = "com.main.entity.World" parameterType = "com.main.entity.World" resultMap="countryMap">
       SELECT
              id, name
       FROM
              map.country
       WHERE
              id = #{mapId}
</select>
<select id = "findProvince" resultType = "com.main.entity.Province" parameterType = "com.main.entity.Province" resultMap="provinceList">
       SELECT
              pro_id AS proId, name
       FROM
              map.province
       WHERE
              country_id = #{id}
</select>

<select id = "findCity" resultType = "com.main.entity.City" parameterType = "com.main.entity.City" resultMap="cityList">
       SELECT
              city_id AS cityId, name
       FROM
              map.province
       WHERE
              pro_id = #{id}
</select>

@Mapper

public interface findMapData{

       World findChina(Integer id); //调用的是xml中的 <select id = "findChina" /> 这个方法

}