从堆栈跟踪看来，您使用的是 DatabaseUtils 内部关闭，因为 DatabaseUtils 无法序列化无法通过n/w转换，请尝试序列化 DatabaseUtils . 而且，你可以
DatabaseUtils scala object ```
.. DatabaseUtils extends Serializable

改变 DatabaseUtils 下面的代码&类内示例移除变量dbconfig&url，添加以下内容 val dbObj = new DatabaseUtils(ConfigFactory.parseFile(new File(config))) ```
class DatabaseUtils(url: String, username: String, password: String) {

val driver = "com.mysql.jdbc.Driver"

def executeSelectQuery(qry: String): List[String] = {

var dbString : ArrayBuffer[String] = ArrayBuffer.empty[String]
var conn:Connection = null
try {
  Class.forName(driver)
  conn = DriverManager.getConnection(url, username, password)
  val statement = conn.createStatement
  val rs = statement.executeQuery(qry)

  while (rs.next) dbString += rs.getString("db_string")

} catch {
  case e: Exception => e.printStackTrace
}
finally {
  conn.close()
}
dbString.toList

}
}

object DatabaseUtils {
def apply(dbConfig:Config): DatabaseUtils = {
val url = "jdbc:mysql://" + dbConfig.getString("db.host") +":"+ dbConfig.getString("db.port") + "/" + dbConfig.getString("db.database") + "?useSSL=false"
new DatabaseUtils(url, dbConfig.getString("db.username") ,dbConfig.getString("db.password"))
}
}