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Scala并发之 Future ExecutionContext     所属分类 scala 浏览量 183
Java   java.util.concurrent
scala  scala.concurrent
Future ExecutionContext
Future 提供回调函数 避免阻塞


Future 两种状态
未完成
已完成 有返回值 或者 异常 ,Future完成后不可变 

Future object apply 创建 Future 
def apply[T](body: =>T)(implicit @deprecatedName('execctx) executor: ExecutionContext): Future[T] = impl.Future(body)
需要 ExecutionContext 或者 隐式提供
import scala.concurrent.ExecutionContext.Implicits.global


val future = Future[Int] {
  Thread.sleep(1000)
  1
}



回调函数
onComplete onFailure onSuccess 

future.onComplete {
  case Success(result) => println(result)
  case Failure(e) => println("error: " + e.getMessage)
}

future.onSuccess {
  case num => println(num)
}

future.onFailure {
  case e => println(e.getMessage)
}

ExecutionContext与Java中的线程池类似,用来管理线程

Java中 利用 Executors来定义线程池ExecutorService
newFixedThreadPool newSingleThreadExecutor newCachedThreadPool newScheduledThreadPool

ExecutionContext.fromExecutorService 
def fromExecutorService(e : java.util.concurrent.ExecutorService) : scala.concurrent.ExecutionContextExecutorService = {  ... }

val executor = Executors.newFixedThreadPool(3)
val executionContext = ExecutionContext.fromExecutor(executor)


scala future 实例 scala future for 实例 scala Future sequence java并发包JUC简介 java线程池系列文章汇总

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scala future for 实例

scala Future sequence

scala Promise

scala type 关键字

Scala 抽象类(abstract) 和 特质(trait) 异同

typesafe config 读取配置