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将Typesafe配置解析为case类

typesafe-config case-class adt scala

Georg Heiler · 技术社区 · 8 年前

什么是配件 案例类别 要分析:

input {
    foo {
      bar = "a"
      baz = "b"
    }

    bar {
      bar = "a"
      baz = "c"
      other= "foo"
    }
}

从类型安全HOCON配置通过 https://github.com/kxbmap/configs ?

如何通过ADT读取?看看他们的例子,我不知道如何构建一个类层次结构,其中一些类具有不同数量的字段,但可以继承一些字段。

sealed trait Tree
case class Branch(value: Int, left: Tree, right: Tree) extends Tree
case object Leaf extends Tree

我的示例如下:

import at.tmobile.bigdata.utils.config.ConfigurationException
import com.typesafe.config.ConfigFactory
import configs.syntax._

val txt =
  """
    |input {
    |    foo {
    |      bar = "a"
    |      baz = "b"
    |      type = "foo"
    |    }
    |
    |    bar {
    |      bar = "a"
    |      baz = "c"
    |      other= "foo"
    |      type="bar"
    |    }
    |}
  """.stripMargin

val config = ConfigFactory.parseString(txt)
config

sealed trait Input{ def bar: String
  def baz:String }
case class Foo(bar: String, baz: String) extends Input
case class Bar(bar:String, baz:String, other:String)extends Input

config.extract[Input].toEither match {
  case Right(s) => s
  case Left(l) =>
    throw new ConfigurationException(
      s"Failed to start. There is a problem with the configuration: " +
        s"${l.messages.foreach(println)}"
    )
}

失败于:

No configuration setting found for key 'type'

1 回复 | 直到 8 年前

Szymon Jednac 8 年前

如果 input 配置将始终包括 2 字段(如示例所示 txt 价值i、 e.只是 foo 和 bar ),则可以这样做:

val txt =
  """
    |input {
    |    foo {
    |      bar = "a"
    |      baz = "b"
    |      type = "foo"
    |    }
    |
    |    bar {
    |      bar = "a"
    |      baz = "c"
    |      other = "foo"
    |      type = "bar"
    |    }
    |}
  """.stripMargin

sealed trait Input {
  def bar: String
  def baz: String
}
case class Foo(bar: String, baz: String) extends Input
case class Bar(bar: String, baz: String, other:String) extends Input

case class Inputs(foo: Foo, bar: Bar)

val result = ConfigFactory.parseString(txt).get[Inputs]("input")
println(result)

输出:

Success(Inputs(Foo(a,b),Bar(a,c,foo)))

如果您打算设置序列 ,那么您应该在的配置和分析中反映这一点 Seq[Input] :

val txt =
  """
    |inputs = [
    |    {
    |      type = "Foo"
    |      bar = "a"
    |      baz = "b"
    |    }
    |
    |    {
    |      type = "Bar"
    |      bar = "a"
    |      baz = "c"
    |      other= "foo"
    |    }
    |]
  """.stripMargin

sealed trait Input {
  def bar: String
  def baz: String
}
case class Foo(bar: String, baz: String) extends Input
case class Bar(bar: String, baz: String, other: String) extends Input

val result = ConfigFactory.parseString(txt).get[Seq[Input]]("inputs")
println(result)

输出:

Success(Vector(Foo(a,b), Bar(a,c,foo)))