java spark转换算子union、intersection、subtract

/**
 * # _*_ coding:utf-8 _*_
 * # Author:xiaoshubiao
 * # Time : 2020/5/14 8:33
 **/
import org.apache.spark.SparkConf;
import org.apache.spark.api.java.JavaRDD;
import org.apache.spark.api.java.JavaSparkContext;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class union_test {
    public static void main(String[] args) {
        SparkConf conf = new SparkConf().setMaster("local[*]").setAppName("union_test");
        JavaSparkContext sc = new JavaSparkContext(conf);
        List<String> list = Arrays.asList("a","b","c");
        List<String> list2 = Arrays.asList("d","e","f","h","a");
        JavaRDD<String> parallelize = sc.parallelize(list, 1);
        JavaRDD<String> parallelize2 = sc.parallelize(list2,1);
        parallelize.union(parallelize2).collect().forEach(x->System.out.println("union-并集结果："+x));//是并集不去重的结果，在这a会出现两个
        parallelize.intersection(parallelize2).collect().forEach(x->System.out.println("intersection-交集结果："+x));
        parallelize.subtract(parallelize2).collect().forEach(x->System.out.println("intersection-差集结果："+x));

    }
}