Scala Seq for Java in Java？-Java 学习之路

我need to use SparkContext instead of JavaSparkContext for the accumulableCollection (if you don't agree check out the linked question请回答！）

Clarified Question: SparkContext is available in Java but wants a Scala sequence. How do I make it happy -- in Java?

我有这个代码做一个简单的 jsc.parallelize 我正在使用JavaSparkContext，但SparkContext想要一个Scala集合 . 我在这里想到我正在构建一个Scala Range并将其转换为Java列表，不知道如何将该核心Range作为Scala Seq，这就是parallelize from SparkContext is asking for .

// The JavaSparkContext way, was trying to get around MAXINT limit, not the issue here
    // setup bogus Lists of size M and N for parallelize
    //List<Integer> rangeM = rangeClosed(startM, endM).boxed().collect(Collectors.toList());
    //List<Integer> rangeN = rangeClosed(startN, endN).boxed().collect(Collectors.toList());

接下来是金钱线，如何在Java中创建Scala Seq以实现并行化？

// these lists above need to be scala objects now that we switched to SparkContext
    scala.collection.Seq<Integer> rangeMscala = scala.collection.immutable.List(startM to endM);

    // setup sparkConf and create SparkContext
    ... SparkConf setup
    SparkContext jsc = new SparkContext(sparkConf);

    RDD<Integer> dataSetMscala = jsc.parallelize(rangeMscala);

1 回答

你应该这样使用它：

scala.collection.immutable.Range rangeMscala = 
  scala.collection.immutable.Range$.MODULE$.apply(1, 10);

SparkContext sc = new SparkContext();

RDD dataSetMscala = 
  sc.parallelize(rangeMscala, 3, scala.reflect.ClassTag$.MODULE$.Object());

希望能帮助到你！问候

回复于 2024-04-18T12:44:50+08:00

Scala Seq for Java in Java？

1 回答

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