Slick GetResult 中 Joda DateTime 和 sql Timestamp 之间的类型不匹配错误

Question

我想检索类型为 DateTime 的列的数据，我正在使用 jodatime。即使我有一个自定义 TypeMapper，我也会收到类型不匹配错误。

[error] C:\sample\modules\test\com\samp\user.scala:55: type mismatch;
[error]  found   : java.sql.Timestamp
[error]  required: org.joda.time.DateTime
[error]             result.nextTimestamp,
[error]                    ^
[error] one error found

这里是代码

import org.specs2.mutable.Specification
import scala.slick.session.Database
import Database.threadLocalSession
import scala.slick.jdbc.{GetResult, StaticQuery => Q}
import Q.interpolation
import org.joda.time.DateTime
import scala.slick.lifted.{MappedTypeMapper,TypeMapper}
import java.sql.Timestamp

class UserSpec
  extends Specification {

  "User tests " should {
    "get all the user data in db" in
      new WithServer() {

      val db = Database.forURL(url = "jdbc:h2:/path/to/db-file", driver = "com.mysql.jdbc.Driver")

      implicit def dateTimeTypeMapper = MappedTypeMapper.base[DateTime, Timestamp] (
        dateTime => new Timestamp(dateTime.getMillis()),
        timeStamp => new DateTime(timeStamp)
      )

      case class user(
        id: String,
        name: String,
        joinedAt: DateTime,
        description: Option[String]
      )

      implicit val getUserResult: GetResult[user] = 
        GetResult( result =>
         user(
           result.nextString,
           result.nextString,
           result.nextTimestamp,
           result.nextStringOption)
      )

      db withSession {
        val usr = Q.queryNA[user]("SELECT * FROM user").list()
        usr foreach println
      }
    }
  }
}

我不确定为什么这不起作用。非常感谢任何帮助或指示。

Answer 1

这里的问题是result.nextTimestamp 返回一个java.sql.Timestamp（result 是 JDBC ResultSet）。如果你想把它变成DateTime，我认为它有一个构造函数。所以你会写：

implicit val getUserResult: GetResult[user] = 
  GetResult( result =>
    user(
      result.nextString,
      result.nextString,
      new DateTime(result.nextTimestamp),
      result.nextStringOption)
    )