public class WordCountWindow {

    public static void main(String[] args) throws Exception {

        // 1. 初始化流式运行环境

        Configuration conf = new Configuration();

        StreamExecutionEnvironment env = StreamExecutionEnvironment.createLocalEnvironmentWithWebUI(conf);

        // 2. 设置时间处理类型，这里设置的方式处理时间

        env.setStreamTimeCharacteristic(TimeCharacteristic.ProcessingTime);

        // 3. 定义数据源，每秒发送一个hadoop单词

        DataStreamSource<String> wordDS = env.addSource(new RichSourceFunction<String>() {

            private boolean isCanaled = false;

            @Override

            public void run(SourceContext<String> ctx) throws Exception {

                while (!isCanaled) {

                    ctx.collect("hadooop");

                    Thread.sleep(1000);

                }

            }

            @Override

            public void cancel() {

                isCanaled = true;

            }

        });

        // 4. 每5秒进行一次，分组统计

        // 4.1 转换为元组

        wordDS.map(word -> Tuple2.of(word, 1))

                // 指定返回类型

                .returns(Types.TUPLE(Types.STRING, Types.INT))

                // 按照单词进行分组

                .keyBy(t -> t.f0)

                // 滚动窗口，3秒计算一次

                .timeWindow(Time.seconds(3))

                .reduce(new ReduceFunction<Tuple2<String, Integer>>() {

                    @Override

                    public Tuple2<String, Integer> reduce(Tuple2<String, Integer> value1, Tuple2<String, Integer> value2) throws Exception {

                        return Tuple2.of(value1.f0, value1.f1 + value2.f1);

                    }

                }, new RichWindowFunction<Tuple2<String, Integer>, Tuple2<String, Integer>, String, TimeWindow>() {

                    @Override

                    public void apply(String word, TimeWindow window, Iterable<Tuple2<String, Integer>> input, Collector<Tuple2<String, Integer>> out) throws Exception {

                        // 打印窗口开始、结束时间

                        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

                        System.out.println("窗口开始时间:" + sdf.format(window.getStart())

                                + " 窗口结束时间：" + sdf.format(window.getEnd())

                                + " 窗口计算时间:" + sdf.format(System.currentTimeMillis()));

                        int sum = 0;

                        Iterator<Tuple2<String, Integer>> iterator = input.iterator();

                        while(iterator.hasNext()) {

                            Integer count = iterator.next().f1;

                            sum += count;

                        }

                        out.collect(Tuple2.of(word, sum));

                    }

                }).print();

        env.execute("app");

    }

}