flink學習-使用IDEA+SCALA編寫WordCount

 

目錄

　　1 前置條件

　　　　1.1 系統環境

　　　　1.2 確認環境

　　2 創建項目

 

　　3 配置項目

　　4 編寫代碼

　　5 運行項目

1 前置條件

1.1 系統環境

　　需要安裝maven、Java、Scala。

1.2 確認條件

　　確認Java和Scala版本，Scala版本與后續項目配置有關系。

　　1）確認Java版本

　　　　

 

 

 　　2）確認Scala版本

　　　　

 

 

 

2 創建項目

　　使用maven創建：

　　　　創建命令：

　　　　　　　　mvn archetype:generate -DarchetypeGroupId=org.apache.flink -DarchetypeArtifactId=flink-quickstart-scala -DarchetypeVersion=1.9.0

　　　　　注：-DarchetypeVersion=1.9.0為flink版本號，要一致，也可以在創建后的項目進行修改。

3 配置項目

　　1） 查看pom.xml文件

　　　　

 

 

 　　　　　將flink和scala版本號與系統環境保持一致

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<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>groupId</groupId>
    <artifactId>artifactId</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>Flink Quickstart Job</name>
    <url>http://www.myorganization.org</url>

    <repositories>
        <repository>
            <id>apache.snapshots</id>
            <name>Apache Development Snapshot Repository</name>
            <url>https://repository.apache.org/content/repositories/snapshots/</url>
            <releases>
                <enabled>false</enabled>
            </releases>
            <snapshots>
                <enabled>true</enabled>
            </snapshots>
        </repository>
    </repositories>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <flink.version>1.9.2</flink.version>
        <scala.binary.version>2.12</scala.binary.version>
        <scala.version>2.12.11</scala.version>
    </properties>

    <dependencies>
        <!-- Apache Flink dependencies -->
        <!-- These dependencies are provided, because they should not be packaged into the JAR file. -->
        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-scala_${scala.binary.version}</artifactId>
            <version>${flink.version}</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-streaming-scala_${scala.binary.version}</artifactId>
            <version>${flink.version}</version>
            <scope>provided</scope>
        </dependency>

        <!-- Scala Library, provided by Flink as well. -->
        <dependency>
            <groupId>org.scala-lang</groupId>
            <artifactId>scala-library</artifactId>
            <version>${scala.version}</version>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-connector-kafka-0.10_2.10</artifactId>
            <version>1.9.2</version>
        </dependency>
        <!-- Add connector dependencies here. They must be in the default scope (compile). -->

        <!-- Example:

        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-connector-kafka-0.10_${scala.binary.version}</artifactId>
            <version>${flink.version}</version>
        </dependency>
        -->

        <!-- Add logging framework, to produce console output when running in the IDE. -->
        <!-- These dependencies are excluded from the application JAR by default. -->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>1.7.7</version>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
            <scope>runtime</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <!-- We use the maven-shade plugin to create a fat jar that contains all necessary dependencies. -->
            <!-- Change the value of <mainClass>...</mainClass> if your program entry point changes. -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-shade-plugin</artifactId>
                <version>3.0.0</version>
                <executions>
                    <!-- Run shade goal on package phase -->
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>shade</goal>
                        </goals>
                        <configuration>
                            <artifactSet>
                                <excludes>
                                    <exclude>org.apache.flink:force-shading</exclude>
                                    <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>
                                <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                                    <mainClass>groupId.StreamingJob</mainClass>
                                </transformer>
                            </transformers>
                        </configuration>
                    </execution>
                </executions>
            </plugin>

            <!-- Java Compiler -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>

            <!-- Scala Compiler -->
            <plugin>
                <groupId>net.alchim31.maven</groupId>
                <artifactId>scala-maven-plugin</artifactId>
                <version>3.2.2</version>
                <executions>
                    <execution>
                        <goals>
                            <goal>compile</goal>
                            <goal>testCompile</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>

            <!-- Eclipse Scala Integration -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-eclipse-plugin</artifactId>
                <version>2.8</version>
                <configuration>
                    <downloadSources>true</downloadSources>
                    <projectnatures>
                        <projectnature>org.scala-ide.sdt.core.scalanature</projectnature>
                        <projectnature>org.eclipse.jdt.core.javanature</projectnature>
                    </projectnatures>
                    <buildcommands>
                        <buildcommand>org.scala-ide.sdt.core.scalabuilder</buildcommand>
                    </buildcommands>
                    <classpathContainers>
                        <classpathContainer>org.scala-ide.sdt.launching.SCALA_CONTAINER</classpathContainer>
                        <classpathContainer>org.eclipse.jdt.launching.JRE_CONTAINER</classpathContainer>
                    </classpathContainers>
                    <excludes>
                        <exclude>org.scala-lang:scala-library</exclude>
                        <exclude>org.scala-lang:scala-compiler</exclude>
                    </excludes>
                    <sourceIncludes>
                        <sourceInclude>**/*.scala</sourceInclude>
                        <sourceInclude>**/*.java</sourceInclude>
                    </sourceIncludes>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.codehaus.mojo</groupId>
                <artifactId>build-helper-maven-plugin</artifactId>
                <version>1.7</version>
                <executions>
                    <!-- Add src/main/scala to eclipse build path -->
                    <execution>
                        <id>add-source</id>
                        <phase>generate-sources</phase>
                        <goals>
                            <goal>add-source</goal>
                        </goals>
                        <configuration>
                            <sources>
                                <source>src/main/scala</source>
                            </sources>
                        </configuration>
                    </execution>
                    <!-- Add src/test/scala to eclipse build path -->
                    <execution>
                        <id>add-test-source</id>
                        <phase>generate-test-sources</phase>
                        <goals>
                            <goal>add-test-source</goal>
                        </goals>
                        <configuration>
                            <sources>
                                <source>src/test/scala</source>
                            </sources>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

    <!-- This profile helps to make things run out of the box in IntelliJ -->
    <!-- Its adds Flink's core classes to the runtime class path. -->
    <!-- Otherwise they are missing in IntelliJ, because the dependency is 'provided' -->
    <profiles>
        <profile>
            <id>add-dependencies-for-IDEA</id>

            <activation>
                <property>
                    <name>idea.version</name>
                </property>
            </activation>

            <dependencies>
                <dependency>
                    <groupId>org.apache.flink</groupId>
                    <artifactId>flink-scala_${scala.binary.version}</artifactId>
                    <version>${flink.version}</version>
                    <scope>compile</scope>
                </dependency>
                <dependency>
                    <groupId>org.apache.flink</groupId>
                    <artifactId>flink-streaming-scala_${scala.binary.version}</artifactId>
                    <version>${flink.version}</version>
                    <scope>compile</scope>
                </dependency>
                <dependency>
                    <groupId>org.scala-lang</groupId>
                    <artifactId>scala-library</artifactId>
                    <version>${scala.version}</version>
                    <scope>compile</scope>
                </dependency>

                <dependency>
                    <groupId>org.apache.flink</groupId>
                    <artifactId>flink-connector-kafka_2.12</artifactId>
                    <version>1.9.2</version>
                </dependency>
            </dependencies>
        </profile>
    </profiles>

</project>

 

　　　　　　

　　2）Project Structure

　　　　添加scala環境。

　　　　

 

 

 　　　　注：第一次使用時IDEA默認不安裝Scala插件，需要自己安裝（打開個scala后綴文件，IDEA會自動提示安裝）。

　　4 編寫代碼

　　　　1）新建Scala文件

　　　　　　

 

 

 　　　　　　注：命名規范為首字母大寫駝峰形式

　　　　　　

 

 

 　　

　　　　2）編寫代碼

　　　　　　

import org.apache.flink.api.scala._
object WordCount {
  def main(args: Array[String]): Unit = {

    // set up the execution environment
    val env = ExecutionEnvironment.getExecutionEnvironment

    // get input data
    val text = env.fromElements(
      "hello, world!",
      "hello, world!",
      "hello, world!")

    val counts = text.flatMap { _.toLowerCase.split(" ") }
      .map { (_, 1) }
      .groupBy(0)
      .sum(1)

    // execute and print result
    counts.print()


  }
}

 

　　5 運行項目

　　　　1）輸出結果