AccumulatorOperator

package com.bjsxt.spark.others;

import org.apache.spark.Accumulator;
import org.apache.spark.SparkConf;
import org.apache.spark.api.java.JavaSparkContext;
import org.apache.spark.api.java.function.VoidFunction;
/**
* 累加器在Driver端定义赋初始值和读取，在Executor端累加。
* @author root
*
*/
public class AccumulatorOperator {
public static void main(String[] args) {
SparkConf conf = new SparkConf();
conf.setMaster("local").setAppName("accumulator");
JavaSparkContext sc = new JavaSparkContext(conf);
final Accumulator<Integer> accumulator = sc.accumulator(0);
// accumulator.setValue(1000);
sc.textFile("./words.txt").foreach(new VoidFunction<String>() {

/**
*
*/
private static final long serialVersionUID = 1L;

@Override
public void call(String t) throws Exception {
accumulator.add(1);
// System.out.println(accumulator.value());
// System.out.println(accumulator);
}
});
System.out.println(accumulator.value());
sc.stop();

}
}