插件如何与注入和对象(而不是播放2.4中的类)一起使用

问题描述

我需要将play mailer插件迁移到play 2.4.我检查了play 2.4的一些示例，发现所有示例都使用了插件类.我不想将其转换为类.它可以与Object一起使用吗?

I need to migrate the play mailer plugin for play 2.4.I checked some samples for play 2.4 and found that all the samples uses classes for plugin. I don't want to convert it to class. Is there any way for it to work with Object?

样品

class MyComponent @Inject() (mailerClient: MailerClient) {
    def sendEmail {
       val email = Email(......)
       ......
       mailerClient.send(email)
    }
}

原始代码

object MailHandler{
  def sendEmail(to: String) = {
try {
  val email = play.api.libs.mailer.Email(...)
  MailerPlugin.send(email)
}catch{
  case ex:Exception=>PlayLogger.instance.error(ex.getMessage)
}
}

推荐答案

我假设您使用一个对象而不是一个类来使它成为单例.

I assume you use an object instead of a class in order to make it a singleton.

有一个用于单例的特殊注释(-> @Singleton)，可确保仅创建了一个类实例.

There is a special annotation for singletons (-> @Singleton) which makes sure there is only one instance of your class created.

尽管他们仍然使用实际的类而不是对象.

Although they still use an actual class instead of an object.

一个例子可能像这样:

import javax.inject._

@Singleton
class MailerClient {
  def sendEmail(to: String) = {
    try {
      val email = play.api.libs.mailer.Email(...)
       MailerPlugin.send(email)
    }catch{
      case ex:Exception=>PlayLogger.instance.error(ex.getMessage)
    }
  }
}

看一下文档: https://www.playframework.com/documentation/2.4.x/ScalaDependencyInjection#Singletons

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