在Javardd排序

Question

我用java来玩火花.我想对我的地图进行排序.事实上,我有这样的javaRDD:

JavaPairRDD<String, Integer> rebondCountURL = session_rebond_2.mapToPair(new PairFunction<Tuple2<String, String>, String, String>() {
        @Override
        public Tuple2<String, String> call(Tuple2<String, String> stringStringTuple2) throws Exception {
            return new Tuple2<String, String>(stringStringTuple2._2, stringStringTuple2._1);
        }
    }).groupByKey().map(new PairFunction<Tuple2<String, Iterable<String>>, Tuple2<String, Integer>>() {
        @Override
        public Tuple2<String, Integer> call(Tuple2<String, Iterable<String>> stringIterableTuple2) throws Exception {
            Iterable<String> strings = stringIterableTuple2._2;
            List<String> b = new ArrayList<String>();
            for (String s : strings) {
                b.add(s);
            }
            return new Tuple2<String, Integer>(stringIterableTuple2._1, b.size());
        }
    });

我想使用Sortby对此Java Rdd进行排序(以便使用Integer进行排序).

你能帮帮我吗？

先感谢您.

Answer 1

您需要创建一个从每个元素中提取排序键的函数.我们的代码示例

final JavaRDD<Something> stage2 = stage1.sortBy( new Function<Something, Long>() {
  private static final long serialVersionUID = 1L;

  @Override
  public Long call( Something value ) throws Exception {
    return value.getTime();
  }
}, true, 1 );