第二章 快速上手

2.1 搭建 maven 工程 FlinkTutorial

2.1.1 pom 文件

<?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>flink_example</groupId>
    <artifactId>flink</artifactId>
    <version>1.0-SNAPSHOT</version>
    <dependencies>
        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-scala_2.11</artifactId>
            <version>1.7.2</version>
         </dependency>
        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-streaming-scala_2.11</artifactId>
            <version>1.7.2</version>
        </dependency>
    </dependencies>
    <build>
        <plugins>
    <!-- 该插件用于将 Scala 代码编译成 class 文件 -->
            <plugin>
                <groupId>net.alchim31.maven</groupId>
                <artifactId>scala-maven-plugin</artifactId>
                <version>3.4.6</version> <executions>
            <execution>
            <!-- 声明绑定到 maven 的 compile 阶段 --> <goals>
            <goal>testCompile</goal> </goals>
            </execution>
            </executions>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-assembly-plugin</artifactId>
                <version>3.0.0</version>
                <configuration>
                 <descriptorRefs>
                     <descriptorRef>jar-with-dependencies</descriptorRef>
                 </descriptorRefs>
                </configuration>
                 <executions><execution>
        <id>make-assembly</id>
        <phase>package</phase> <goals>
        <goal>single</goal> </goals>
    </execution> </executions>
    </plugin>
    </plugins> </build>
</project>

2.2 批处理 wordcount

WordCount.scala

package org.gz
import org.apache.flink.api.scala._
import org.apache.flink.api.scala.{AggregateDataSet, DataSet, ExecutionEnvironment}
object WordCount {
  def main(args: Array[String]): Unit = {
      val env = ExecutionEnvironment.getExecutionEnvironment
    val inputPath="/Users/gaozhen/IdeaProjects/flink/src/main/resources/a.txt"
    val inputDS: DataSet[String] = env.readTextFile(inputPath)
    val wordCountDS: AggregateDataSet[(String, Int)] = inputDS.flatMap(_.split(" ")).map((_,1)).groupBy(0).sum(1)
    wordCountDS.print()
  }
}

2.3 流处理 wordcount

StreamWordCount.scala

package org.gz.org.gz
import org.apache.flink.api.java.utils.ParameterTool
import org.apache.flink.streaming.api.scala.{DataStream, StreamExecutionEnvironment}
import org.apache.flink.streaming.api.scala._
object StreamWordCount {
  def main(args: Array[String]): Unit = {
    val params: ParameterTool = ParameterTool.fromArgs(args)
    val host:String = params.get("host")
    val port:Int = params.getInt("port")
    val env = StreamExecutionEnvironment.getExecutionEnvironment
    val textDStream:DataStream[String]= env.socketTextStream(host,port)
    val dataStream : DataStream[(String, Int)] =
      textDStream.flatMap(_.split("\\s")).map((_,1)).keyBy(0).sum(1)
    dataStream.print().setParallelism(1)
    env.execute("Socket stream word count")
  }
}

测试：开启服务端，在启动程序

nc -lk 7777

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