flink dataset 分组后如何实现内容拼接呢？

可以这样写

ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment(); env.fromElements(Tuple3.of(1.0, 2.0, 1), Tuple3.of(2.0, 2.0, 1),Tuple3.of(3.0,2.0,1), Tuple3.of(1.0, 2.0, 2), Tuple3.of(2.0, 2.0, 2),Tuple3.of(3.0,2.0,2)) .map((MapFunction<Tuple3<Double, Double, Integer>, Tuple3<String, Double, Integer>>) t -> Tuple3.of(String.valueOf(t.f0), t.f1, t.f2)).groupBy(2) .reduce((ReduceFunction<Tuple3<String, Double, Integer>>) (tuple, t1) -> Tuple3.of(tuple.f0 + "#" + t1.f0, tuple.f1, tuple.f2)).print(); env.execute(); 结果： (1.0#2.0#3.0,2.0,1) (1.0#2.0#3.0,2.0,2)*来自志愿者整理的FLINK邮件归档