播放框架2.1 - 无法找到一个隐含的ExecutionContext

Question

我打电话web服务这样的：

WS 
    .url(url) 
    .get 
    .map { response => // error occurs on this line 
    response.status match { 
     case 200 => Right(response.json) 
     case status => Left(s"Problem accessing api, status '$status'") 
    } 
} 

完整的错误：Error: Cannot find an implicit ExecutionContext, either require one yourself or import ExecutionContext.Implicits.global

Answer 1

据this issue，它是固定的文档。我需要添加以下导入：

import play.api.libs.concurrent.Execution.Implicits._ 

Answer 2

另外一种方式：

import scala.concurrent.ExecutionContext.Implicits.global 

Answer 3

由于播放2.4，您可以通过吉斯依赖注入默认execution context：注射。

class Foo @Inject()()(implicit ec:ExecutionContext) { 

def bar() = { 
    WS.url(url) 
    .get 
    .map { response => // error occurs on this line 
     response.status match { 
     case 200 => Right(response.json) 
     case status => Left(s"Problem accessing api, status '$status'") 
    } 
    } 
}