java + spark:org.apache.spark.SparkException:作业已中止:任务不可序列化:java.io.NotSerializableException

Question

我是新手,并试图运行示例JavaSparkPi.java,它运行良好,但因为我必须在另一个java中使用它我将所有东西从main复制到类中的方法并尝试调用主要方法,它说

org.apache.spark.SparkException:作业已中止:任务不可序列化:java.io.NotSerializableException

代码如下所示:

public class JavaSparkPi {

public void cal(){
    JavaSparkContext jsc = new JavaSparkContext("local", "JavaLogQuery");
    int slices = 2;
    int n = 100000 * slices;

    List<Integer> l = new ArrayList<Integer>(n);
    for (int i = 0; i < n; i++) {
        l.add(i);
    }

    JavaRDD<Integer> dataSet = jsc.parallelize(l, slices);

    System.out.println("count is: "+ dataSet.count());
    dataSet.foreach(new VoidFunction<Integer>(){
        public void call(Integer i){
            System.out.println(i);
        }
    });

    int count = dataSet.map(new Function<Integer, Integer>() {
        @Override
        public Integer call(Integer integer) throws Exception {
            double x = Math.random() * 2 - 1;
            double y = Math.random() * 2 - 1;
            return (x * x + y * y < 1) ? 1 : 0;
        }
    }).reduce(new Function2<Integer, Integer, Integer>() {
        @Override
        public Integer call(Integer integer, Integer integer2) throws Exception {
            return integer + integer2;
        }
    });

    System.out.println("Pi is roughly " + 4.0 * count / n);
}

public static void main(String[] args) throws Exception {

    JavaSparkPi myClass = new JavaSparkPi();
    myClass.cal();
}
}

有谁有这个想法？谢谢!

Answer 1

嵌套函数包含对包含对象(JavaSparkPi)的引用.所以这个对象将被序列化.为此,它需要可序列化.简单易行:

public class JavaSparkPi implements Serializable {
  ...