獲取用油滑

Question

最近點我有以下的情況下類：

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

Postgres裏我有一個表的子塊contient ID：INT， BLOCK_ID：詮釋， 名稱：字符串， geom_location：地理， sub_block_geom：地理

我定義一個函數返回最近的指定點的子塊

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()))) 

和我的請求返回正確的結果，但後我得到«異常在線程「主」java.lang.NullPointerException«因爲sub_block_geom在我的數據庫中爲空，所以我認爲解決方案是改變隱式val getSubBlock或用篩選器編寫查詢，sortedBy，...我不知道該怎麼做

Answer 1

嗯......我不太清楚你的問題，因爲缺少很多必需的細節。但從我所看到的情況來看，您只需要在getSubBlock中妥善處理null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) 
}