说明

1. 启动 tcp服务器

2. 启动 flink 代码，连接 tcp服务器

3. tcp服务器输入单词 和 时间戳（表示事件时间）

如下：

111,1640261670000
111,1640261669000
111,1640261671000
111,1640261675000
111,1640261673000
111,1640261674000
111,1640261672000
111,1640261680000
111,1640261660000
111,1640261690000

解释：

• 111：表示数据，任何字符串都行，由于代码中会执行 keyBy()，所以最好相同

• 1640261670000：表示时间戳，可通过下面代码查看时间：
  System.out.println(new Date(1640261670000l))，显示时间为：
  Thu Dec 23 20:14:30 CST 2021

代码

import org.apache.flink.api.common.functions.MapFunction;
import org.apache.flink.api.java.tuple.Tuple;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.streaming.api.TimeCharacteristic;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.datastream.SingleOutputStreamOperator;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.api.functions.AssignerWithPeriodicWatermarks;
import org.apache.flink.streaming.api.functions.windowing.WindowFunction;
import org.apache.flink.streaming.api.watermark.Watermark;
import org.apache.flink.streaming.api.windowing.assigners.TumblingEventTimeWindows;
import org.apache.flink.streaming.api.windowing.time.Time;
import org.apache.flink.streaming.api.windowing.windows.TimeWindow;
import org.apache.flink.util.Collector;
import org.apache.flink.util.OutputTag;

import javax.annotation.Nullable;
import java.text.SimpleDateFormat;
import java.util.*;


public class Paixu {



    public static void main(String[] args) throws Exception {
        //定义socket的端口号
        int port = 9090;
        //获取运行环境
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();

        //设置使用eventtime，默认是使用processtime
//        env.setStreamTimeCharacteristic(TimeCharacteristic.EventTime);

        //设置并行度为1,默认并行度是当前机器的cpu数量
        env.setParallelism(1);

        //连接socket获取输入的数据
        DataStream<String> text = env.socketTextStream("hadoop1", port, "\n");

        //解析输入的数据
        DataStream<Tuple2<String, Long>> inputMap = text.map(new MapFunction<String, Tuple2<String, Long>>() {
            @Override
            public Tuple2<String, Long> map(String value) throws Exception {
                String[] arr = value.split(",");
                return new Tuple2<>(arr[0], Long.parseLong(arr[1]));
            }
        });

        //抽取timestamp和生成watermark
        DataStream<Tuple2<String, Long>> waterMarkStream = inputMap.assignTimestampsAndWatermarks(new AssignerWithPeriodicWatermarks<Tuple2<String, Long>>() {

            Long currentMaxTimestamp = 0L;
            final Long maxOutOfOrderness = 10000L;// 最大允许的乱序时间是10s
            Long currentWaterMark=0L;
            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");
            /**
             * 定义生成watermark的逻辑
             * 默认100ms被调用一次
             */
            @Nullable
            @Override
            public Watermark getCurrentWatermark() {
                currentWaterMark = currentMaxTimestamp - maxOutOfOrderness;
                System.out.println("当前水位线:" + currentWaterMark);
                return new Watermark(currentWaterMark);

            }

            //定义如何提取timestamp
            @Override
            public long extractTimestamp(Tuple2<String, Long> element, long previousElementTimestamp) {
                long eventTime = element.f1;
                currentMaxTimestamp = Math.max(eventTime, currentMaxTimestamp);
                System.out.println("key:"+element.f0+",eventtime:["+element.f1+"|"+sdf.format(element.f1)+"],currentMaxTimestamp:["+currentMaxTimestamp+"|"+
                        sdf.format(currentMaxTimestamp)+"],watermark:["+getCurrentWatermark().getTimestamp()+"|"+sdf.format(getCurrentWatermark().getTimestamp())+"]");
                return eventTime;
            }
        });

        //保存被丢弃的数据
        OutputTag<Tuple2<String, Long>> outputTag = new OutputTag<Tuple2<String, Long>>("late-data"){};
        //注意，由于getSideOutput方法是SingleOutputStreamOperator子类中的特有方法，所以这里的类型，不能使用它的父类dataStream。
        SingleOutputStreamOperator<String> window = waterMarkStream.keyBy(t->t.f0)
                .window(TumblingEventTimeWindows.of(Time.seconds(10)))//按照消息的EventTime分配窗口，和调用TimeWindow效果一样
                //.allowedLateness(Time.seconds(2))//允许数据迟到2秒
                .sideOutputLateData(outputTag)
                .apply(new WindowFunction<Tuple2<String, Long>, String, String, TimeWindow>() {
                    /**
                     * 对window内的数据进行排序，保证数据的顺序
                     * @param key
                     * @param window
                     * @param input
                     * @param out
                     * @throws Exception
                     */
                    @Override
                    public void apply(String key, TimeWindow window, Iterable<Tuple2<String, Long>> input, Collector<String> out) throws Exception {

                        List<Tuple2<String, Long>> list = new ArrayList();
                        Iterator<Tuple2<String, Long>> it = input.iterator();
                        while (it.hasNext()) {
                            list.add(it.next());
                        }
                        list.sort(new Comparator<Tuple2<String, Long>>() {
                            @Override
                            public int compare(Tuple2<String, Long> o1, Tuple2<String, Long> o2) {
                                int ret=0;
                                if(o2.f1 > o1.f1){
                                    ret=-1;
                                }else if(o2.f1 < o1.f1){
                                    ret=1;
                                }else{//等于
                                    ret=0;
                                }
                                return ret;
                            }
                        });
                        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");
                        String result = key + "," + list.size() + "," + sdf.format(list.get(0).f1) + ","
                                + sdf.format(list.get(list.size() - 1).f1)
                                + ",window start:" + sdf.format(window.getStart()) + ",window end:" + sdf.format(window.getEnd());
                        System.out.println("list:");
                        for(Tuple2<String, Long> t:list){
                            System.out.println(t.toString());
                        }
                        System.out.println("--");


                        out.collect(result);
                    }
                });
        //把迟到的数据暂时打印到控制台，实际中可以保存到其他存储介质中
        DataStream<Tuple2<String, Long>> sideOutput = window.getSideOutput(outputTag);
        sideOutput.print("sideOutput:::");
        //测试-把结果打印到控制台
        window.print("window:::");

        //注意：因为flink是懒加载的，所以必须调用execute方法，上面的代码才会执行
        env.execute("eventtime-watermark");

    }
}