《深入理解Spark-核心思想与源码分析》（三）第三章SparkContext的初始化

3.1 SparkContext概述

　　SparkConf负责配置参数，主要通过ConcurrentHaspMap来维护各种Spark的配置属性。

class SparkConf(loadDefaults: Boolean) extends Cloneable with Logging with Serializable {

  import SparkConf._

  /** Create a SparkConf that loads defaults from system properties and the classpath */
  def this() = this(true)

  private val settings = new ConcurrentHashMap[String, String]()

  @transient private lazy val reader: ConfigReader = {
    val _reader = new ConfigReader(new SparkConfigProvider(settings))
    _reader.bindEnv(new ConfigProvider {
      override def get(key: String): Option[String] = Option(getenv(key))
    })
    _reader
  }
....

原文地址：https://www.cnblogs.com/sunrunzhi/p/10169868.html