大数据（9f）Flink双流JOIN

概述

Flink双流JOIN可用算子或SQL实现，FlinkSQL的JOIN在另一篇讲
算子JOIN中较常用的是intervalJoin

开发环境

WIN10+IDEA

<properties>
    <maven.compiler.source>8</maven.compiler.source>
    <maven.compiler.target>8</maven.compiler.target>
    <flink.version>1.14.6</flink.version>
    <scala.binary.version>2.12</scala.binary.version>
    <slf4j.version>2.0.3</slf4j.version>
    <log4j.version>2.17.2</log4j.version>
    <lombok.version>1.18.24</lombok.version>
</properties>
<dependencies>
    <!-- Flink -->
    <dependency>
        <groupId>org.apache.flink</groupId>
        <artifactId>flink-java</artifactId>
        <version>${flink.version}</version>
    </dependency>
    <dependency>
        <groupId>org.apache.flink</groupId>
        <artifactId>flink-streaming-java_${scala.binary.version}</artifactId>
        <version>${flink.version}</version>
    </dependency>
    <dependency>
        <groupId>org.apache.flink</groupId>
        <artifactId>flink-clients_${scala.binary.version}</artifactId>
        <version>${flink.version}</version>
    </dependency>
    <dependency>
        <groupId>org.apache.flink</groupId>
        <artifactId>flink-runtime-web_${scala.binary.version}</artifactId>
        <version>${flink.version}</version>
    </dependency>
    <!-- 日志 -->
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-api</artifactId>
        <version>${slf4j.version}</version>
    </dependency>
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-log4j12</artifactId>
        <version>${slf4j.version}</version>
    </dependency>
    <dependency>
        <groupId>org.apache.logging.log4j</groupId>
        <artifactId>log4j-to-slf4j</artifactId>
        <version>${log4j.version}</version>
    </dependency>
    <!-- 简化JavaBean书写 -->
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <version>${lombok.version}</version>
    </dependency>
</dependencies>

使用状态列表实现 INNER JOIN（双流connect后CoProcessFunction）

import org.apache.flink.api.common.functions.RuntimeContext;
import org.apache.flink.api.common.state.ListState;
import org.apache.flink.api.common.state.ListStateDescriptor;
import org.apache.flink.api.common.typeinfo.Types;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.configuration.Configuration;
import org.apache.flink.streaming.api.datastream.ConnectedStreams;
import org.apache.flink.streaming.api.datastream.DataStreamSource;
import org.apache.flink.streaming.api.datastream.KeyedStream;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.api.functions.co.CoProcessFunction;
import org.apache.flink.util.Collector;

public class Hello {
    
    
    public static void main(String[] args) throws Exception {
    
    
        //创建执行环境，设置并行度
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment().setParallelism(1);
        //创建双流
        DataStreamSource<Tuple2<String, Long>> d1 = env.fromElements(
                Tuple2.of("a", 2L),
                Tuple2.of("a", 3L),
                Tuple2.of("b", 5L)
        );
        DataStreamSource<Tuple2<String, String>> d2 = env.fromElements(
                Tuple2.of("a", "A"),
                Tuple2.of("b", "B"),
                Tuple2.of("c", "C")
        );
        //双流KeyBy
        KeyedStream<Tuple2<String, Long>, String> kd1 = d1.keyBy(t -> t.f0);
        KeyedStream<Tuple2<String, String>, String> kd2 = d2.keyBy(t -> t.f0);
        //connect
        ConnectedStreams<Tuple2<String, Long>, Tuple2<String, String>> c = kd1.connect(kd2);
        //CoProcessFunction<IN1, IN2, OUT>
        c.process(new CoProcessFunction<Tuple2<String, Long>, Tuple2<String, String>, String>() {
    
    
            ListState<Tuple2<String, Long>> l1;
            ListState<Tuple2<String, String>> l2;
            @Override
            public void open(Configuration parameters) {
    
    
                RuntimeContext r = getRuntimeContext();
                l1 = r.getListState(new ListStateDescriptor<>("L1", Types.TUPLE(Types.STRING, Types.LONG)));
                l2 = r.getListState(new ListStateDescriptor<>("L2", Types.TUPLE(Types.STRING, Types.STRING)));
            }

            @Override
            public void processElement1(Tuple2<String, Long> value, Context ctx, Collector<String> out) throws Exception {
    
    
                l1.add(value);
                for (Tuple2<String, String> value2 : l2.get()) {
    
    
                    out.collect(value + "==>" + value2);
                }
            }

            @Override
            public void processElement2(Tuple2<String, String> value, Context ctx, Collector<String> out) throws Exception {
    
    
                l2.add(value);
                for (Tuple2<String, Long> value1 : l1.get()) {
    
    
                    out.collect(value1 + "==>" + value);
                }
            }
        }).print();
        //流环境执行
        env.execute();
    }
}

基于间隔的JOIN（Interval Join）

import lombok.AllArgsConstructor;
import lombok.Data;
import org.apache.flink.api.common.eventtime.SerializableTimestampAssigner;
import org.apache.flink.api.common.eventtime.WatermarkStrategy;
import org.apache.flink.streaming.api.datastream.KeyedStream;
import org.apache.flink.streaming.api.datastream.SingleOutputStreamOperator;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.api.functions.co.ProcessJoinFunction;
import org.apache.flink.streaming.api.windowing.time.Time;
import org.apache.flink.util.Collector;

public class Hello {
    
    
    public static void main(String[] args) throws Exception {
    
    
        //创建执行环境，设置并行度
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment().setParallelism(1);
        //创建双流和时间时间水位线策略
        SingleOutputStreamOperator<U> d1 = env.fromElements(
                new U("a", 3 * 1000L),
                new U("b", 8 * 1000L),
                new U("c", 13 * 1000L)
        ).assignTimestampsAndWatermarks(WatermarkStrategy.<U>forMonotonousTimestamps().withTimestampAssigner(
                (SerializableTimestampAssigner<U>) (element, recordTimestamp) -> element.timestamp));
        SingleOutputStreamOperator<U> d2 = env.fromElements(
                new U("a", 4 * 1000L),
                new U("b", 6 * 1000L),
                new U("b", 7 * 1000L),
                new U("c", 10 * 1000L)
        ).assignTimestampsAndWatermarks(WatermarkStrategy.<U>forMonotonousTimestamps().withTimestampAssigner(
                (SerializableTimestampAssigner<U>) (element, recordTimestamp) -> element.timestamp));
        //键控流
        KeyedStream<U, String> k1 = d1.keyBy(u -> u.id);
        KeyedStream<U, String> k2 = d2.keyBy(u -> u.id);
        //基于间隔进行联合
        k1.intervalJoin(k2).between(Time.seconds(-2L), Time.seconds(1L)).process(
                new ProcessJoinFunction<U, U, String>() {
    
    
                    @Override
                    public void processElement(U left, U right, Context ctx, Collector<String> out) {
    
    
                        out.collect(left + " ==> " + right);
                    }
                }).print();
        //流环境执行
        env.execute();
    }

    @Data
    @AllArgsConstructor
    public static class U {
    
    
        String id;
        Long timestamp;
    }
}

结果
Hello.U(id=a, timestamp=3000) ==> Hello.U(id=a, timestamp=4000)
Hello.U(id=b, timestamp=8000) ==> Hello.U(id=b, timestamp=6000)
Hello.U(id=b, timestamp=8000) ==> Hello.U(id=b, timestamp=7000)

双流JOIN是双向的，下面两种写法是等价的

k1.intervalJoin(k2).between(Time.seconds(-2L), Time.seconds(1L))

k2.intervalJoin(k1).between(Time.seconds(-1L), Time.seconds(2L))

基于窗口的JOIN（Window Join）

窗口JOIN包括滚动窗口、滑动窗口、会话窗口

滚动窗口JOIN

滑动窗口JOIN

会话窗口JOIN

语法

stream.join(otherStream)
    .where(<KeySelector>)
    .equalTo(<KeySelector>)
    .window(<WindowAssigner>)
    .apply(<JoinFunction>)

下面只展示滚动窗口JOIN

import lombok.AllArgsConstructor;
import lombok.Data;
import org.apache.flink.api.common.eventtime.SerializableTimestampAssigner;
import org.apache.flink.api.common.eventtime.WatermarkStrategy;
import org.apache.flink.api.common.functions.JoinFunction;
import org.apache.flink.streaming.api.datastream.SingleOutputStreamOperator;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.api.windowing.assigners.TumblingEventTimeWindows;
import org.apache.flink.streaming.api.windowing.time.Time;

public class Hello {
    
    
    public static void main(String[] args) throws Exception {
    
    
        //创建执行环境，设置并行度
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment().setParallelism(1);
        //创建双流和时间时间水位线策略
        SingleOutputStreamOperator<U> d1 = env.fromElements(
                new U("a", 2000L),
                new U("b", 4000L)
        ).assignTimestampsAndWatermarks(WatermarkStrategy.<U>forMonotonousTimestamps().withTimestampAssigner(
                (SerializableTimestampAssigner<U>) (element, recordTimestamp) -> element.timestamp));
        SingleOutputStreamOperator<U> d2 = env.fromElements(
                new U("a", 3999L),
                new U("b", 3999L),
                new U("b", 5999L)
        ).assignTimestampsAndWatermarks(WatermarkStrategy.<U>forMonotonousTimestamps().withTimestampAssigner(
                (SerializableTimestampAssigner<U>) (element, recordTimestamp) -> element.timestamp));
        //窗口JOIN
        d1
                .join(d2)
                .where(u -> u.id)
                .equalTo(u -> u.id)
                .window(TumblingEventTimeWindows.of(Time.seconds(2)))
                .apply((JoinFunction<U, U, String>) (first, second) -> first + " ==> " + second)
                .print();
        //流环境执行
        env.execute();
    }

    @Data
    @AllArgsConstructor
    public static class U {
    
    
        String id;
        Long timestamp;
    }
}

结果
Hello.U(id=a, timestamp=2000) ==> Hello.U(id=a, timestamp=3999)
Hello.U(id=b, timestamp=4000) ==> Hello.U(id=b, timestamp=5999)
（4000和3999不在同一个滚动窗口，4000和5999在同一个滚动窗口）