實現兩組資料的Join操作。

第一組：i, i*i

第二組：i, 'a'+i

join之後的結果是：i, i*i, 'a'+i

public class SparkSample {
    private static final Pattern SPACE = Pattern.compile(" ");

    public static void main(String args[]) {
        SparkConf sparkConf = new SparkConf();
        sparkConf.setAppName("SparkJavaWordCount");
        sparkConf.setMaster("local");

        JavaSparkContext context = new JavaSparkContext(sparkConf);

        List<Integer> data = Arrays.asList(1,2,3,4,5);
        JavaRDD<Integer> distData= context.parallelize(data);

        JavaPairRDD<Integer, Integer> firstRDD = distData.mapToPair(new PairFunction<Integer, Integer, Integer>() {
            @Override
            public Tuple2<Integer, Integer> call(Integer integer) throws Exception {
                return new Tuple2(integer, integer*integer);
            }
        });

        JavaPairRDD<Integer, String> secondRDD = distData.mapToPair(new PairFunction<Integer, Integer, String>() {
            @Override
            public Tuple2<Integer, String> call(Integer integer) throws Exception {
                return new Tuple2(integer, String.valueOf((char)('a' + integer)));
            };
        });


        JavaPairRDD<Integer, Tuple2<Integer, String>> joinRDD = firstRDD.join(secondRDD);

        JavaRDD<String> result = joinRDD.map(new Function<Tuple2<Integer, Tuple2<Integer, String>>, String>() {
            @Override
            public String call(Tuple2<Integer, Tuple2<Integer, String>> integerTuple2Tuple2) throws Exception {
                int key = integerTuple2Tuple2._1();
                int value1 = integerTuple2Tuple2._2()._1();
                String value2 = integerTuple2Tuple2._2()._2();
                return key + " " + value1 + " " + value2;
            }
        });

        List<String> reslist = result.collect();
        for(String str : reslist) {
            System.out.println(str);
        }
        context.stop();
    }
}