如何从播放缓存中获取对象(标量) [英] How to get object from Play cache (scala)

问题描述

如何从Play缓存(标量)获取对象

How to get object from Play cache (scala)

要设置的代码:

play.api.cache.Cache.set("mykey98",  new Product(98), 0)

要获取的代码:

val product1: Option[Any]  = play.api.cache.Cache.get("mykey98")

我得到Option对象.如何获得第一步中存储的实际Product对象.

I get Option object. How to get actual Product object I stored in first step.

推荐答案

首先，我建议使用带有类型参数的Cache.getAs.这样，您就不会被Option[Any]所困扰.有几种方法可以做到这一点.在我的示例中，我将使用String，但是它将与任何其他类相同.我的首选方式是通过模式匹配:

First and foremost, I would suggest using Cache.getAs, which takes a type parameter. That way you won't be stuck with Option[Any]. There are a few ways you can do this. In my example, I'll use String, but it will work the same with any other class. My preferred way is by pattern matching:

import play.api.cache.Cache

Cache.set("mykey", "cached string", 0)

val myString:String = Cache.getAs[String]("mykey") match {
    case Some(string) => string
    case None => SomeOtherClass.getNewString() // or other code to handle an expired key
}

此示例在模式匹配方面有点过分简化，但是当需要根据键的存在来分支代码时，我认为它是一种更好的方法.您也可以使用Cache.getOrElse:

This example is a bit over-simplified for pattern matching, but I think its a nicer method when needing to branch code based on the existence of a key. You could also use Cache.getOrElse:

val myString:String = Cache.getOrElse[String]("mykey") {
    SomeOtherClass.getNewString()
}

在特定情况下，将String替换为Product，然后更改代码以处理如果键不存在(例如设置默认键)会发生的情况.

In your specific case, replace String with Product, then change the code to handle what will happen if the key does not exist (such as setting a default key).

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