Flink WordCount实例讲解

    摘要：本文主要讲了一个Flink的简单的可以本地运行的wordCount程序

本文工程下载：https://github.com/appleappleapple/BigDataLearning

1、工程目录结构

2、pom文件

<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/maven-v4_0_0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<groupId>com.lin</groupId>
	<artifactId>Flink-Demo</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>${project.artifactId}</name>

	<properties>
		<maven.compiler.source>1.6</maven.compiler.source>
		<maven.compiler.target>1.6</maven.compiler.target>
		<encoding>UTF-8</encoding>
		<scala.version>2.11.5</scala.version>
		<scala.compat.version>2.11</scala.compat.version>
	</properties>

	<dependencies>
		<dependency>
			<groupId>org.scala-lang</groupId>
			<artifactId>scala-library</artifactId>
			<version>${scala.version}</version>
		</dependency>

		<dependency>
			<groupId>org.apache.flink</groupId>
			<artifactId>flink-scala_2.11</artifactId>
			<version>1.1.2</version>
		</dependency>
		<dependency>
			<groupId>org.apache.flink</groupId>
			<artifactId>flink-clients_2.11</artifactId>
			<version>1.1.2</version>
		</dependency>

		<dependency>
			<groupId>org.apache.flink</groupId>
			<artifactId>flink-streaming-scala_2.11</artifactId>
			<version>1.1.2</version>
		</dependency>
	</dependencies>

	<build>
		<sourceDirectory>src/main/scala</sourceDirectory>
		<testSourceDirectory>src/test/scala</testSourceDirectory>
		<plugins>
			<plugin>
				<!-- see http://davidb.github.com/scala-maven-plugin -->
				<groupId>net.alchim31.maven</groupId>
				<artifactId>scala-maven-plugin</artifactId>
				<version>3.2.0</version>
				<executions>
					<execution>
						<goals>
							<goal>compile</goal>
							<goal>testCompile</goal>
						</goals>
						<configuration>
							<args>
								<arg>-make:transitive</arg>
								<arg>-dependencyfile</arg>
								<arg>${project.build.directory}/.scala_dependencies</arg>
							</args>
						</configuration>
					</execution>
				</executions>
			</plugin>
			<plugin>
				<groupId>org.apache.maven.plugins</groupId>
				<artifactId>maven-surefire-plugin</artifactId>
				<version>2.18.1</version>
				<configuration>
					<useFile>false</useFile>
					<disableXmlReport>true</disableXmlReport>
					<!-- If you have classpath issue like NoDefClassError,... -->
					<!-- useManifestOnlyJar>false</useManifestOnlyJar -->
					<includes>
						<include>**/*Test.*</include>
						<include>**/*Suite.*</include>
					</includes>
				</configuration>
			</plugin>
		</plugins>
	</build>
</project>

3、代码

package com.lin.flink.demo

import org.apache.flink.api.java.utils.ParameterTool
import org.apache.flink.api.scala._
import org.apache.flink.core.fs.FileSystem.WriteMode

/**
 * 可以直接本地运行
 */
object WordCount {

  def main(args: Array[String]) {
    val env = ExecutionEnvironment.createLocalEnvironment(1)

    //从本地读取文件
    val text = env.readTextFile("D:/Java/flink-1.2.0-bin-hadoop27-scala_2.11/flink-1.2.0-bin-hadoop27-scala_2.11/flink-1.2.0/README.txt")

    //单词统计
    val counts = text.flatMap { _.toLowerCase.split("\\W+") filter { _.nonEmpty } }
      .map { (_, 1) }
      .groupBy(0)
      .sum(1)

    //输出结果
    counts.print()

    //保存结果到txt文件
    counts.writeAsText("D:/output.txt", WriteMode.OVERWRITE)
    env.execute("Scala WordCount Example")

  }
}

直接运行，输出结果如下

保存的外部文件

本文工程下载：https://github.com/appleappleapple/BigDataLearning