一个Flink消费Kafka的消息流的例子

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使用Flink消费Kafka消息流

FlinkJob定义程序执行的配置以及过滤及持久的相关类，首先完成对所有配置的加载（加载的类定义的成员变量必须是可序列化的）后再执行。

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public class FlinkJob {

    public  static void main(String[] args) {
        StreamExecutionEnvironment env = StreamExecutionEnvironment .getExecutionEnvironment();
        Properties properties = new Properties();
        properties.setProperty("bootstrap.servers", PropertyUtil.getProperty("kafka.servers"));
        properties.setProperty("zookeeper.connect", PropertyUtil.getProperty("kafka.zookeeper"));
        properties.setProperty("group.id", PropertyUtil.getProperty("kafka.group"));
        properties.setProperty("flink.partition-discovery.interval-millis", PropertyUtil.getProperty("kafka.partition-discovery.interval-millis"));

        // 添加数据源
        DataStream<String> text = env.addSource(
            new FlinkKafkaConsumer010<>(PropertyUtil.getProperty("kafka.topic"),
                new SimpleStringSchema(), properties).setStartFromEarliest()
            ).name("FlinkKafkaConsumer010: FlinkJob");

        // 对数据源进行过滤
        DataStream<Object> transformedEvent =
            text.filter(new FlinkTransformer.Filter())
            .map(new FlinkTransformer.Map());

        // 设置执行并行度
        transformedEvent.getExecutionConfig().setParallelism(1);
        // 设置数据持久的类
        transformedEvent.addSink(new FlinkSink());
        // execute program
        try {
            env.execute("FlinkJob");
        } catch (Exception e) {
            log.error("Error when execute FlinkJob", e);
        }
    }
}

FlinkTransformer

FlinkTransformer来完成对数据的过滤和封装，filter方法完成对数据过滤的实现，map方法来对数据进行反序列化，返回需要的对象。

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public class FlinkTransformer {

    public static class Filter implements FilterFunction<String> {

        @Override
        public boolean filter(String value) throws Exception {
            // 数据过滤
            return true;
        }
    }
    public static class Map implements MapFunction<String, Object> {

        @Override
        public Object map(String value) throws Exception {
            Object o = new Object();
            // 数据反序列化
            // 处理value
            return o;
        }
    }
}

FlinkSink

FlinkSink这里是对数据的持久。open方法可以在方法invoke执行前进行一些准备工作。invoke方法是主要完成数据持久的相关逻辑。

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public class FlinkSink extends RichSinkFunction<Object> {

    private static final long serialVersionUID = 1L;

    @Override
    public void open(Configuration parameters) throws Exception {
        // 处理开始之前的操作
    }

    @Override
    public void close() throws Exception {}

    @Override
    public void invoke(Object obj, Context context) throws Exception {
        if (obj == null) {
            return;
        }
       // 具体对消息的处理
    }
}

pom.xml 配置

主要配置Flink和Kafka的相关依赖

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<?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.job</groupId>
    <artifactId>flink-job</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>flink-job</name>
    <description>flink job</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.4.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
        <swagger.version>2.9.2</swagger.version>
        <flink.version>1.6.0</flink.version>
        <druid-version>1.1.9</druid-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>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <exclusions>
                <!-- 去除不需要使用的web组件 -->
                <exclusion>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-starter-tomcat</artifactId>
                </exclusion>
                <!-- 去除该依赖是为了防止上传job到flink server上引起jar包冲突 -->
                <exclusion>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-starter-logging</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>org.springframework</groupId>
                    <artifactId>spring-web</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <!--<dependency>-->
            <!--<groupId>org.springframework.boot</groupId>-->
            <!--<artifactId>spring-boot-starter-data-jpa</artifactId>-->
        <!--</dependency>-->

        <!-- mongodb -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-mongodb</artifactId>
        </dependency>

        <!-- Swagger -->
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger2</artifactId>
            <version>${swagger.version}</version>
        </dependency>
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger-ui</artifactId>
            <version>${swagger.version}</version>
        </dependency>

        <!-- fastjson -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.49</version>
        </dependency>

        <!-- lambok -->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.16.20</version>
            <scope>provided</scope>
        </dependency>

        <!-- apache common-->
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
            <version>3.7</version>
        </dependency>

        <!-- httpClient -->
        <dependency>
            <groupId>commons-httpclient</groupId>
            <artifactId>commons-httpclient</artifactId>
            <version>3.1</version>
        </dependency>
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpcore</artifactId>
            <version>4.4.10</version>
        </dependency>
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>4.5.6</version>
        </dependency>
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpmime</artifactId>
            <version>4.5.6</version>
        </dependency>

        <!-- flink -->
        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-java</artifactId>
            <version>${flink.version}</version>
            <exclusions>
                <exclusion>
                    <groupId>log4j</groupId>
                    <artifactId>*</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>org.slf4j</groupId>
                    <artifactId>slf4j-log4j12</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-streaming-java_2.11</artifactId>
            <version>${flink.version}</version>
            <exclusions>
                <exclusion>
                    <groupId>log4j</groupId>
                    <artifactId>*</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>org.slf4j</groupId>
                    <artifactId>slf4j-log4j12</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-clients_2.11</artifactId>
            <version>${flink.version}</version>
            <exclusions>
                <exclusion>
                    <groupId>log4j</groupId>
                    <artifactId>*</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>org.slf4j</groupId>
                    <artifactId>slf4j-log4j12</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-jdbc</artifactId>
            <version>${flink.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-jdbc</artifactId>
            <version>${flink.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-table_2.11</artifactId>
            <version>${flink.version}</version>
            <scope>provided</scope>
        </dependency>

        <!-- kafaka -->
        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-connector-kafka-0.10_2.11</artifactId>
            <version>${flink.version}</version>
        </dependency>

    </dependencies>

    <build>
        <!--<plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>-->
        <plugins>

            <!-- Java Compiler -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.1</version>
                <configuration>
                    <source>${java.version}</source>
                    <target>${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>3.0.0</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>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>

        <pluginManagement>
            <plugins>

                <!-- If you want to use Java 8 Lambda Expressions uncomment the following lines -->
                <!--
                <plugin>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <configuration>
                        <source>${java.version}</source>
                        <target>${java.version}</target>
                        <compilerId>jdt</compilerId>
                    </configuration>
                    <dependencies>
                        <dependency>
                            <groupId>org.eclipse.tycho</groupId>
                            <artifactId>tycho-compiler-jdt</artifactId>
                            <version>0.21.0</version>
                        </dependency>
                    </dependencies>
                </plugin>
                -->

                <!-- 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>[3.0.0,)</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>