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Question

我有以下案例类：

case class Block(
                         
id: Option[Int] = None,
                         
blockId: Int,
                         
name: String,
                         
location: Option[Point] = None,
                         
geometry: Option[Geometry] = None,
                                           
)

在postgres中我有一个表SubBlock contient id：int， block_id：Int， name：String， geom_location：地理， sub_block_geom：geography

我定义了一个函数来返回最接近指定点的子块

override def getNearestSubBlock(point: Point): Future[SubBlock] = {
      
val query = sql"""SELECT sub_block_id,block_id,name,ST_AsText(geom_location),sub_block_geom from now.sub_block order by ST_Distance(geom_location, ST_MakePoint(${point.getX()}, ${point.getY()})::geography) limit 1""".as[SubBlock].head
      
db.run(query)
    
}

implicit val getSubBlock = GetResult(r => SubBlock(r.nextIntOption(), r.nextInt(), r.nextString(), Option(Location.location2Point(Location.fromWKT(r.nextString()))), Option(new WKTReader().read(r.nextString())))

我的请求返回了正确的结果，但在我得到了«在线程中的异常“主”java.lang.NullPointerException«因为我的数据库中的sub_block_geom为null，所以我认为解决方案是更改隐式val getSubBlock或使用filter，sortedBy，...编写查询，我不知道该怎么做

Answer 1

嗯......我对你的问题不太确定，因为缺少很多必需的细节。但从我所看到的情况来看，您只需要正确处理null中getSubBlock的可能性。

implicit val getSubBlock = GetResult(r => {
  val id = r.nextIntOption()
  val blockId = r.nextInt()
  val location: Option[Point] = r.nextStringOption().map(s => Location.location2Point(Location.fromWKT(s)))
  val geometry: Option[Geometry] = r.nextStringOption().map(s => new WKTReader().read(s)))

  SubBlock(id, blockId, location, geometry)
}