问题描述：Akka持久化：JDBC MySQL没有足够的工作示例

解决方法： 要在Akka中使用JDBC和MySQL进行持久化，需要配置Akka的持久化插件以使用JDBC存储。

以下是一个示例配置文件，显示如何配置Akka的持久化插件以使用JDBC MySQL：

akka.persistence {
  journal {
    plugin = "jdbc-journal"
    jdbc-journal {
      class = "akka.persistence.jdbc.journal.MySQLJournal"
      driver = "com.mysql.jdbc.Driver"
      url = "jdbc:mysql://localhost:3306/mydatabase"
      user = "myuser"
      password = "mypassword"
      tables {
        journal = "journal"
        meta = "meta"
      }
    }
  }
  snapshot-store {
    plugin = "jdbc-snapshot-store"
    jdbc-snapshot-store {
      class = "akka.persistence.jdbc.snapshot.MySQLSnapshotStore"
      driver = "com.mysql.jdbc.Driver"
      url = "jdbc:mysql://localhost:3306/mydatabase"
      user = "myuser"
      password = "mypassword"
      tables {
        snapshot = "snapshot"
      }
    }
  }
}

上述配置文件中，我们使用了jdbc-journal和jdbc-snapshot-store插件，并将它们配置为使用MySQL作为数据库。

接下来，我们需要为Akka应用程序添加所需的库依赖项。在build.sbt文件中添加以下依赖项：

libraryDependencies += "com.typesafe.akka" %% "akka-persistence-jdbc" % "3.0.4"
libraryDependencies += "com.typesafe.akka" %% "akka-persistence-jdbc-mysql" % "3.0.4"
libraryDependencies += "mysql" % "mysql-connector-java" % "8.0.21"

然后，我们可以使用以下示例代码来演示如何使用Akka的持久化插件进行持久化操作：

import akka.actor.{Actor, ActorLogging, ActorSystem, Props}
import akka.persistence.{PersistentActor, SnapshotOffer}

case class ExampleCommand(data: String)
case class ExampleEvent(data: String)

class ExamplePersistentActor extends PersistentActor with ActorLogging {
  override def persistenceId: String = "example-persistent-actor"

  var state: List[String] = List.empty[String]

  override def receiveCommand: Receive = {
    case ExampleCommand(data) =>
      persist(ExampleEvent(data)) { event =>
        log.info(s"Persisted: $event")
        state = event.data :: state
      }
    case "print" =>
      log.info(s"Current state: $state")
    case SnapshotOffer(_, snapshot: List[String]) =>
      state = snapshot
  }

  override def receiveRecover: Receive = {
    case event: ExampleEvent =>
      log.info(s"Recovered: $event")
      state = event.data :: state
  }
}

val system = ActorSystem("example-system")
val persistentActor = system.actorOf(Props[ExamplePersistentActor], "example-persistent-actor")

persistentActor ! ExampleCommand("data1")
persistentActor ! ExampleCommand("data2")
persistentActor ! "print"

在上面的示例代码中，我们定义了一个持久化Actor ExamplePersistentActor，它接收ExampleCommand消息，并将其持久化为ExampleEvent事件。还定义了print消息以打印当前状态。我们通过向ExamplePersistentActor发送ExampleCommand消息来测试持久化功能。

请注意，上述示例仅提供了一个基本的示例，更复杂的用例可能需要更复杂的代码和配置。这里提供的示例代码和配置应该足够让你开始使用Akka的JDBC MySQL持久化插件。