Spark之BroadCast

package com.uplooking.bigdata.core.p3;
 
import org.apache.spark.SparkConf;
import org.apache.spark.SparkContext;
import org.apache.spark.api.java.JavaRDD;
import org.apache.spark.api.java.JavaSparkContext;
import org.apache.spark.broadcast.Broadcast;
 
import java.util.Arrays;
import java.util.List;
 
/**
 * Spark使用广播变量进行计算
 */
public class JavaSparkBroadCastApp {
    public static void main(String[] args) {
        if(args == null || args.length < 1) {
            System.err.println("Usage :");
            System.exit(-1);
        }
        SparkConf conf = new SparkConf();
        conf.setAppName(JavaSparkBroadCastApp.class.getSimpleName());
        conf.setMaster("local[2]");
        JavaSparkContext sc = new JavaSparkContext(conf);
 
        List list = Arrays.asList(1, 2, 3, 4, 5);
        JavaRDD listRDD = sc.parallelize(list);
 
        int times = Integer.valueOf(args[0].trim());
        //设置一个广播变量来解决
        Broadcast timesBC = sc.broadcast(times);
 
 
        //将集合中的每一个元素*times
        JavaRDD retRDD = listRDD.map(ele -> {
            return ele * timesBC.value();
        });
 
        retRDD.foreach(ele -> System.out.println(ele));
    }
}