Question

我按照docs中给出的示例进行操作，但以下操作失败了Codec not found for requested operation: [varchar <-> java.util.UUID]。如何使用Quill提供自定义的Cassandra编解码器？

import java.util.UUID
import javax.inject.Inject
import scala.concurrent.ExecutionContext.Implicits.global
import scala.concurrent.{Await, Future}
import io.getquill.{CassandraAsyncContext, LowerCase, MappedEncoding}
import scala.concurrent.duration._

object Main extends App {

  case class MyOrder(id: String, uuid: UUID)

  trait OrderRepository {
    implicit val encodeUUID: MappedEncoding[UUID, String] = MappedEncoding[UUID, String](_.toString)
    implicit val decodeUUID: MappedEncoding[String, UUID] = MappedEncoding[String, UUID](UUID.fromString)

    def list(): Future[Iterable[MyOrder]]
    def get(id: String): Future[Option[MyOrder]]
  }

  class OrderRepositoryImpl(db: CassandraAsyncContext[LowerCase]) extends OrderRepository {
    import db._

    override def list(): Future[Iterable[MyOrder]] = {
      run(quote(query[MyOrder]))
    }

    override def get(id: String): Future[Option[MyOrder]] = {
      val q = quote {
        (id: String) =>
          query[MyOrder].filter(_.id == id)
      }
      val res = run(q(lift(id.toString)))
      res.map(_.headOption)
    }
  }

  val db = new CassandraAsyncContext[LowerCase]("db")
  val repo = new OrderRepositoryImpl(db)
  val maybeOrder = Await.result(repo.get("id1"), 2 seconds)
  println(s"maybeOrder $maybeOrder")
}

和Cassandra ddl：

CREATE TABLE myorder ( 
id text, 
uuid text, 
PRIMARY KEY (id)
);

INSERT INTO myorder (
id,
uuid
) values (
'id1',
'a8a8a416-2436-4e18-82b3-d5881c8fec1a'
);

显然我可以创建一个uuid字段类型为String的类，但这里的目标是弄清楚如何使用自定义解码器。

未找到Cassandra quill编解码器用于请求的操作

0 个答案: