初学flink-01-wordCount

• 在resource 中添加01_wordCount.txt

hello flink
hello flink

pom

<?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>com.stt.flink</groupId>
    <artifactId>flink-demo</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>
        <!-- https://mvnrepository.com/artifact/org.apache.flink/flink-streaming-scala -->
        <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>

scala

package com.stt.flink

import org.apache.flink.api.scala.{AggregateDataSet, DataSet, ExecutionEnvironment}
import org.apache.flink.api.scala._ // 隐式转换需要

// 批处理wordCount程序
object Ch_01_wordCount {
  def main(args: Array[String]): Unit = {
    // 创建运行环境
    val env = ExecutionEnvironment.getExecutionEnvironment

    // 从文件中读取数据
    val inputPath = this.getClass.getClassLoader.getResource("01_wordCount.txt").getPath

    val inputDS: DataSet[String] = env.readTextFile(inputPath)

    // 分词之后，对单词进行groupby 分组，然后用sum进行聚合
    val wordCountDS: AggregateDataSet[(String, Int)] = inputDS
      .flatMap(_.split("\\s+")) // 对每一行进行空格分隔
      .map((_,1)) // 转换为元组
      .groupBy(0) // 对第一个元素进行分组
      .sum(1) // 对第二个元素进行聚合统计

    // 打印输出
    wordCountDS.print()
  }
}

• 结果

SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.
(flink,2)
(hello,2)