grails - 在grails应用中，服务中的字段是否由用户共享？

Question

我对服务中的字段是否由用户共享有疑问吗？我的grails版本是2.3.4。
现在，我有一个 Controller ，该 Controller 具有两个操作，并试图设置并从服务 Realm 获取值(value)。

//This is a controller
class TestController{
  def testService

  def setValue(){
    testService.setValue("123")
  }

  def getValue(){}
    println testService.getValue()
  }
}

//This is a service
class TestService{
  def var

  def setValue(def value){
    var = value
  }

  def getValue(){}
    return var
  }
}

换句话说，如果几个用户在 Controller 中使用 Action getValue，他们是否在服务中共享 var？
谢谢!

Answer 1

是的，默认情况下，所有services都是单例，因此每个Web应用程序只有一个服务实例，但是内部的功能不同步:

By default, access to service methods is not synchronised, so nothing prevents concurrent execution of those methods. In fact, because the service is a singleton and may be used concurrently, you should be very careful about storing state in a service. Or take the easy (and better) road and never store state in a service.

You can change this behaviour by placing a service in a particular scope. The supported scopes are:

prototype - A new service is created every time it is injected into another class
request - A new service will be created per request
flash - A new service will be created for the current and next request only
flow - In web flows the service will exist for the scope of the flow
conversation - In web flows the service will exist for the scope of the conversation. ie a root flow and its sub flows
session - A service is created for the scope of a user session
singleton (default) - Only one instance of the service ever exists