简介：Flink作为目前最火的流式计算平台，近年来发展迅速，吸引了开发者的青睐，接下来我和大家一起了解其中的奥秘。俗话说万事开头难，咱们就从搭建环境开始入手吧！
- 环境配置。Flink是用Java开发的，所以需要Java开发需要的环境，如：jdk、maven、idea等，这些工具作为Java工程师来说并不难，这里不再累述。
- 源码编译。下载地址https://flink.apache.org/downloads.html，笔者目前使用的是1.13.1版本，大家去官网下载最新的即可。加载完导入idea，注释掉没用的编译插件，如：maven-checkstyle-plugin，然后确保setting配置正确，否则会出现错误Could not transfer metadata xxxxx from/to xxxxx，意思是有些依赖拉取不到，这种情况只需要根据依赖去maven仓库中找，然后确保在仓库中可以找到。笔者刚开始编译时出现了一个问题就是因为本地maven settings配置了公司的私服，然后mirrorOf配置的是*，所以flink这子模块单独设置的仓库就没发用了，某些特殊的依赖在私服中又找不到，所以编译出现拉取不到某些包，后面在编译的时候指定了settings文件之后可以了，例如：mvn clean install --settings xxx。编译大约需要半个小时左右，大家需要耐心等待，中途可能出现错误，可能是网络原因，重试之后就没事了。
- 查看编译后的程序是否能正常使用。编译后的程序放在flin-dist中的target/flink-1.13.1-bin下，可以启动目录下的单机模式的集群来测试。
- 构建一个开发项目。
a. quickstart方式构建
java项目构建命令：
mvn archetype:generate
-DarchetypeGroupId=org.apache.flink
-DarchetypeArtifactId=flink-quickstart-java
-DarchetypeVersion=1.13.1
scala项目构建命令：
mvn archetype:generate
-DarchetypeGroupId=org.apache.flink
-DarchetypeArtifactId=flink-quickstart-scala
-DarchetypeVersion=1.13.1
b. Flink1.10之后的版本也可以根据官方给的样例构造
java项目构建命令：
mvn archetype:generate
-DarchetypeGroupId=org.apache.flink
-DarchetypeArtifactId=flink-walkthrough-datastream-java
-DarchetypeVersion=1.13.0
-DgroupId=frauddetection
-DartifactId=frauddetection
-Dversion=0.1
-Dpackage=spendreport
-DinteractiveMode=false
scala项目构建命令：
mvn archetype:generate
-DarchetypeGroupId=org.apache.flink
-DarchetypeArtifactId=flink-walkthrough-datastream-scala
-DarchetypeVersion=1.13.0
-DgroupId=frauddetection
-DartifactId=frauddetection
-Dversion=0.1
-Dpackage=spendreport
-DinteractiveMode=false
说明：walkthrough【代码走查】模块，主要提供了一个准备好的 Flink Maven Archetype 能够快速创建一个包含了必要依赖的 Flink 程序骨架，基于此，你可以把精力集中在编写业务逻辑上即可。 这些已包含的依赖包括 flink-streaming-java、flink-walkthrough-common 等，他们分别是 Flink 应用程序的核心依赖项和这个代码练习需要的数据生成器，当然还包括其他本代码练习所依赖的类。
c. 项目导入idea时可能出现错误
Exception in thread "main" java.lang.NoClassDefFoundError: scala/Predef$
at com.sht.flink.AccessLog$.main(AccessLog.scala:5)
at com.sht.flink.AccessLog.main(AccessLog.scala)
Caused by: java.lang.ClassNotFoundException: scala.Predef$
at java.net.URLClassLoader.findClass(URLClassLoader.java:382)
at java.lang.ClassLoader.loadClass(ClassLoader.java:418)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:355)
at java.lang.ClassLoader.loadClass(ClassLoader.java:351)
... 2 more
只需要注释掉相关依赖的<scope>provided</scope>就可以了。
构建过程日志如下：
build.png
- maven-shade-plugin打包问题。
Flink uses java Service Provider to discover Source/Sink connector. Without this transformer, you will 100% encoutner "org.apache.flink.table.api.NoMatchingTableFactoryException: Could not find a suitable table factory", which happened on me.
<transformers>
<transformer implementation="org.apache.maven.plugins.shade.resource.ServicesResourceTransformer"/>
</transformers>
- Java项目pom文件：
<!--
Licensed to the Apache Software Foundation (ASF) under one
or more contributor license agreements. See the NOTICE file
distributed with this work for additional information
regarding copyright ownership. The ASF licenses this file
to you under the Apache License, Version 2.0 (the
"License"); you may not use this file except in compliance
with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing,
software distributed under the License is distributed on an
"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
KIND, either express or implied. See the License for the
specific language governing permissions and limitations
under the License.
-->
<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.dpf.flink</groupId>
<artifactId>flink-cdc</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>jar</packaging>
<name>Flink Quickstart Job</name>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<flink.version>1.13.1</flink.version>
<cdc.version>1.4.0</cdc.version>
<fastjson.version>1.2.62</fastjson.version>
<target.java.version>1.8</target.java.version>
<scala.binary.version>2.11</scala.binary.version>
<maven.compiler.source>${target.java.version}</maven.compiler.source>
<maven.compiler.target>${target.java.version}</maven.compiler.target>
<log4j.version>2.12.1</log4j.version>
</properties>
<repositories>
<repository>
<id>apache.snapshots</id>
<name>Apache Development Snapshot Repository</name>
<url>https://repository.apache.org/content/repositories/snapshots/</url>
<releases>
<enabled>false</enabled>
</releases>
<snapshots>
<enabled>true</enabled>
</snapshots>
</repository>
</repositories>
<dependencies>
<!-- Apache Flink dependencies -->
<!-- These dependencies are provided, because they should not be packaged into the JAR file. -->
<dependency>
<groupId>org.apache.flink</groupId>
<artifactId>flink-java</artifactId>
<version>${flink.version}</version>
</dependency>
<dependency>
<groupId>org.apache.flink</groupId>
<artifactId>flink-streaming-java_${scala.binary.version}</artifactId>
<version>${flink.version}</version>
</dependency>
<dependency>
<groupId>org.apache.flink</groupId>
<artifactId>flink-clients_${scala.binary.version}</artifactId>
<version>${flink.version}</version>
</dependency>
<dependency>
<groupId>org.apache.flink</groupId>
<artifactId>flink-table-api-java-bridge_${scala.binary.version}</artifactId>
<version>${flink.version}</version>
</dependency>
<dependency>
<groupId>org.apache.flink</groupId>
<artifactId>flink-table-api-scala-bridge_${scala.binary.version}</artifactId>
<version>${flink.version}</version>
</dependency>
<dependency>
<groupId>org.apache.flink</groupId>
<artifactId>flink-table-planner_${scala.binary.version}</artifactId>
<version>${flink.version}</version>
</dependency>
<dependency>
<groupId>org.apache.flink</groupId>
<artifactId>flink-table-planner-blink_${scala.binary.version}</artifactId>
<version>${flink.version}</version>
</dependency>
<dependency>
<groupId>org.apache.flink</groupId>
<artifactId>flink-table-common</artifactId>
<version>${flink.version}</version>
</dependency>
<dependency>
<groupId>org.apache.flink</groupId>
<artifactId>flink-connector-kafka_${scala.binary.version}</artifactId>
<version>${flink.version}</version>
</dependency>
<dependency>
<groupId>com.alibaba.ververica</groupId>
<artifactId>flink-connector-mysql-cdc</artifactId>
<version>${cdc.version}</version>
</dependency>
<dependency>
<groupId>org.apache.flink</groupId>
<artifactId>flink-connector-jdbc_${scala.binary.version}</artifactId>
<version>${flink.version}</version>
</dependency>
<dependency>
<groupId>org.apache.flink</groupId>
<artifactId>flink-walkthrough-common_${scala.binary.version}</artifactId>
<version>${flink.version}</version>
</dependency>
<dependency>
<groupId>org.apache.flink</groupId>
<artifactId>flink-json</artifactId>
<version>${flink.version}</version>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>${fastjson.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.apache.logging.log4j</groupId>
<artifactId>log4j-slf4j-impl</artifactId>
<version>${log4j.version}</version>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-api</artifactId>
<version>${log4j.version}</version>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
<version>${log4j.version}</version>
<scope>runtime</scope>
</dependency>
</dependencies>
<build>
<plugins>
<!-- Java Compiler -->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.1</version>
<configuration>
<source>${target.java.version}</source>
<target>${target.java.version}</target>
</configuration>
</plugin>
<!-- 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>3.1.1</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>org.apache.logging.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>com.dpf.flink.StreamingJob</mainClass>
</transformer>
</transformers>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
<pluginManagement>
<plugins>
<!-- This improves the out-of-the-box experience in Eclipse by resolving some warnings. -->
<plugin>
<groupId>org.eclipse.m2e</groupId>
<artifactId>lifecycle-mapping</artifactId>
<version>1.0.0</version>
<configuration>
<lifecycleMappingMetadata>
<pluginExecutions>
<pluginExecution>
<pluginExecutionFilter>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<versionRange>[3.1.1,)</versionRange>
<goals>
<goal>shade</goal>
</goals>
</pluginExecutionFilter>
<action>
<ignore/>
</action>
</pluginExecution>
<pluginExecution>
<pluginExecutionFilter>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<versionRange>[3.1,)</versionRange>
<goals>
<goal>testCompile</goal>
<goal>compile</goal>
</goals>
</pluginExecutionFilter>
<action>
<ignore/>
</action>
</pluginExecution>
</pluginExecutions>
</lifecycleMappingMetadata>
</configuration>
</plugin>
</plugins>
</pluginManagement>
</build>
</project>
- Scala项目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/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.sht.flink</groupId>
<artifactId>flink-sql</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>jar</packaging>
<name>Flink Quickstart Job</name>
<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>1.13.1</flink.version>
<target.java.version>1.8</target.java.version>
<scala.binary.version>2.11</scala.binary.version>
<scala.version>2.11.12</scala.version>
<log4j.version>2.12.1</log4j.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>${flink.version}</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.apache.flink</groupId>
<artifactId>flink-clients_${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>
</dependency>
<!-- Add connector dependencies here. They must be in the default scope (compile). -->
<!-- Example:
<dependency>
<groupId>org.apache.flink</groupId>
<artifactId>flink-connector-kafka_${scala.binary.version}</artifactId>
<version>${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.apache.logging.log4j</groupId>
<artifactId>log4j-slf4j-impl</artifactId>
<version>${log4j.version}</version>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-api</artifactId>
<version>${log4j.version}</version>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
<version>${log4j.version}</version>
<scope>runtime</scope>
</dependency>
</dependencies>
<build>
<plugins>
<!-- We use the maven-shade plugin to create a fat jar that contains all necessary dependencies. -->
<!-- Change the value of <mainClass>...</mainClass> if your program entry point changes. -->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>3.1.1</version>
<executions>
<!-- Run shade goal on package phase -->
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
<configuration>
<artifactSet>
<excludes>
<exclude>org.apache.flink:force-shading</exclude>
<exclude>com.google.code.findbugs:jsr305</exclude>
<exclude>org.slf4j:*</exclude>
<exclude>org.apache.logging.log4j:*</exclude>
</excludes>
</artifactSet>
<filters>
<filter>
<!-- Do not copy the signatures in the META-INF folder.
Otherwise, this might cause SecurityExceptions when using the JAR. -->
<artifact>*:*</artifact>
<excludes>
<exclude>META-INF/*.SF</exclude>
<exclude>META-INF/*.DSA</exclude>
<exclude>META-INF/*.RSA</exclude>
</excludes>
</filter>
</filters>
<transformers>
<transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
<mainClass>com.sht.flink.StreamingJob</mainClass>
</transformer>
</transformers>
</configuration>
</execution>
</executions>
</plugin>
<!-- Java Compiler -->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.1</version>
<configuration>
<source>${target.java.version}</source>
<target>${target.java.version}</target>
</configuration>
</plugin>
<!-- Scala Compiler -->
<plugin>
<groupId>net.alchim31.maven</groupId>
<artifactId>scala-maven-plugin</artifactId>
<version>3.2.2</version>
<executions>
<execution>
<goals>
<goal>compile</goal>
<goal>testCompile</goal>
</goals>
</execution>
</executions>
<configuration>
<args>
<arg>-nobootcp</arg>
<arg>-target:jvm-${target.java.version}</arg>
</args>
</configuration>
</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>
</project>
