flink scala编写wordcount

开发工具：idea+netcat

1、使用idea新建项目

step1:
新建maven项目

step2:
指定项目基本信息

step3:
pom文件增加flink与scala依赖项

<dependencies>

        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-streaming-scala_2.12</artifactId>
            <version>1.11.2</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.apache.flink/flink-scala -->
        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-scala_2.12</artifactId>
            <version>1.11.2</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.apache.flink/flink-clients -->
        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-clients_2.12</artifactId>
            <version>1.11.2</version>
        </dependency>


    </dependencies>

2、批处理模式：

hello.txt

Hello World
Hello Flink

WordCountBatch.scala

import org.apache.flink.api.scala._
import org.apache.flink.api.scala.ExecutionEnvironment


object WordCountBatch {
  def main(args: Array[String]): Unit = {
    //获取resources下的文件
    val resource = this.getClass.getClassLoader.getResource("hello.txt")
    //获取执行环境
    var env: ExecutionEnvironment = ExecutionEnvironment.getExecutionEnvironment
    //读取文件、分割、过滤、map、分组求和
    var grp = env.readTextFile(resource.getPath).flatMap(_.split(" ")).filter(_.nonEmpty).map((_, 1))
      .groupBy(0).sum(1)
    //打印处理结果
    grp.print()
    //env.execute()
  }
}

执行结果：

3、流式处理模式：

WordCountStream.scala

package com.emoney.learn

import org.apache.flink.api.java.utils.ParameterTool
import org.apache.flink.streaming.api.scala._

object WordCountStream {
  def main(args: Array[String]): Unit = {
    //获取流处理执行环境
    val environment: StreamExecutionEnvironment = StreamExecutionEnvironment.getExecutionEnvironment
  
    //监听host,port socket端口
    val ds = environment.socketTextStream("localhost", 6666)

    //ETL
    ds.flatMap(_.split(" ")).map((_, 1)).keyBy(0).sum(1).print()
    environment.execute()
  }
}

netcat开启socke端口
step1:
https://eternallybored.org/misc/netcat/下载可执行问题
step2:
解压文件并拷贝nc.exe到C:\Windows\System32

step3:
开启socket端口
win+r nc -l -p 6666

运行结果