模拟flink处理无限数据流

如果没有在 linux 环境下安装 flink ，先看我的上一篇文章：如何搭建Linux环境下的flink本地集群-CSDN博客

使用工具：IntelliJ IDEA 2021，Maven 3.6.1

第一步，创建一个空的 Maven 项目，导入依赖

XML 复制代码

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>flinkLearn</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-runtime-web</artifactId>
            <version>${flink.version}</version>
        </dependency>
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
            <version>1.2.11</version>
        </dependency>
        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-streaming-java</artifactId>
            <version>${flink.version}</version>
        </dependency>

        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-clients</artifactId>
            <version>${flink.version}</version>
        </dependency>
    </dependencies>


    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
        <flink.version>1.17.0</flink.version>
    </properties>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-shade-plugin</artifactId>
                <version>3.2.4</version>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>shade</goal>
                        </goals>
                        <configuration>
                            <artifactSet>
                                <excludes>
                                    <exclude>com.google.code.findbugs:jsr305</exclude>
                                    <exclude>org.slf4j:*</exclude>
                                    <exclude>log4j:*</exclude>
                                </excludes>
                            </artifactSet>
                            <filters>
                                <filter>
                                    <!-- Do not copy the signatures in the META-INF folder.
                                    Otherwise, this might cause SecurityExceptions when using the JAR. -->
                                    <artifact>*:*</artifact>
                                    <excludes>
                                        <exclude>META-INF/*.SF</exclude>
                                        <exclude>META-INF/*.DSA</exclude>
                                        <exclude>META-INF/*.RSA</exclude>
                                    </excludes>
                                </filter>
                            </filters>
                            <transformers combine.children="append">
                                <transformer
                                        implementation="org.apache.maven.plugins.shade.resource.ServicesResourceTransformer">
                                </transformer>
                            </transformers>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>


</project>

等等依赖下载完毕

第二步，编写分词处理无界流代码

此刻先不要运行，因为还没有数据源

java 复制代码

import org.apache.flink.api.common.typeinfo.Types;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.streaming.api.datastream.DataStreamSource;
import org.apache.flink.streaming.api.datastream.SingleOutputStreamOperator;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.util.Collector;

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

        //拿到执行环境
        StreamExecutionEnvironment evn = StreamExecutionEnvironment.getExecutionEnvironment();
        //数据源 source
        //注：加 returns 是因为 lambda 表达式无法识别二元组中的类型，故手动指定以避免报错
        DataStreamSource<String> source = evn.socketTextStream("localhost", 8888);
        SingleOutputStreamOperator<Tuple2<String, Integer>> sum = source.flatMap((String value, Collector<Tuple2<String, Integer>> out) -> {
            String[] words = value.split(" ");
            for (String word : words) {
                out.collect(Tuple2.of(word, 1));
            }
        })
        .returns(Types.TUPLE(Types.STRING,Types.INT))
        .keyBy((Tuple2<String, Integer> value) -> value.f0)
        .sum(1);
        //写入,sink
        sum.print();
        //执行
        evn.execute();

    }


}