使用Maven构建Flink第一个项目

0.准备工作

下载Flink并运行！

1.IDEA创建Maven项目

点击左上角File->new Project->后面直接点击下一步->GroupID与artifactId、version随便填写->填写项目名称，点击完成。

注意：Maven打包后的jar包名字就是我们artifactId-version.jar格式，可以适当根据喜好在pom.xml修改。

pom.xml修改：

<dependencies>      <dependency>          <groupId>org.apache.flink</groupId>          <artifactId>flink-streaming-java_2.11</artifactId> <!--2.11为scala.binary.version-->          <version>1.7.2</version> <!--Flink版本号-->      </dependency>  </dependencies>

点击import change即可。

新java class命名为：SocketTextStreamWordCount。

填写下面代码：

import org.apache.flink.api.common.functions.FlatMapFunction;  import org.apache.flink.api.java.tuple.Tuple2;  import org.apache.flink.streaming.api.datastream.DataStreamSource;  import org.apache.flink.streaming.api.datastream.SingleOutputStreamOperator;  import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;  import org.apache.flink.util.Collector;    public class SocketTextStreamWordCount {      public static void main(String[] args) throws Exception {          //参数检查          if (args.length != 2) {              System.err.println("USAGE:nSocketTextStreamWordCount <hostname> <port>");              return;          }            String hostname = args[0];          Integer port = Integer.parseInt(args[1]);              // set up the streaming execution environment          final StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();            //获取数据          DataStreamSource<String> stream = env.socketTextStream(hostname, port);            //计数          SingleOutputStreamOperator<Tuple2<String, Integer>> sum = stream.flatMap(new LineSplitter())                  .keyBy(0)                  .sum(1);            sum.print();            env.execute("Java WordCount from SocketTextStream Example");      }        public static final class LineSplitter implements FlatMapFunction<String, Tuple2<String, Integer>> {            public void flatMap(String s, Collector<Tuple2<String, Integer>> collector) {              String[] tokens = s.toLowerCase().split("\W+");                for (String token: tokens) {                  if (token.length() > 0) {                      collector.collect(new Tuple2<String, Integer>(token, 1));                  }              }          }      }  }