Flink1.8入门：入门实例--流处理SocketWordCount（界面提交+参数传递）

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 * to you under the Apache License, Version 2.0 (the
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 * http://www.apache.org/licenses/LICENSE-2.0
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package com.hadoop.ljs.flink.streaming;

import org.apache.flink.api.common.functions.FlatMapFunction;
import org.apache.flink.api.common.functions.ReduceFunction;
import org.apache.flink.api.java.utils.ParameterTool;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.api.windowing.time.Time;
import org.apache.flink.util.Collector;

/**
 * Implements a streaming windowed version of the "WordCount" program.
 *
 * <p>This program connects to a server socket and reads strings from the socket.
 * The easiest way to try this out is to open a text server (at port 12345)
 * using the <i>netcat</i> tool via
 * <pre>
 * nc -l 12345 on Linux or nc -l -p 12345 on Windows
 * </pre>
 * and run this example with the hostname and the port as arguments.
 */
@SuppressWarnings("serial")
public class SocketWordCount {

  public static void main(String[] args) throws Exception {

    // the host and the port to connect to
    final String hostname;
    final int port;
    try {
      final ParameterTool params = ParameterTool.fromArgs(args);
      hostname = params.has("hostname") ? params.get("hostname") : "localhost";
      port = params.getInt("port");

      /*hostname = "10.124.165.98";
      port = 9999;*/
    } catch (Exception e) {
      System.err.println("No port specified. Please run 'SocketWordCount " +
        "--hostname <hostname> --port <port>', where hostname (localhost by default) " +
        "and port is the address of the text server");
      System.err.println("To start a simple text server, run 'netcat -l <port>' and " +
        "type the input text into the command line");
      return;
    }

    // get the execution environment
    final StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();

    // get input data by connecting to the socket
    DataStream<String> text = env.socketTextStream(hostname, port, "\n");

    // parse the data, group it, window it, and aggregate the counts
    DataStream<WordWithCount> windowCounts = text

        .flatMap(new FlatMapFunction<String, WordWithCount>() {
          @Override
          public void flatMap(String value, Collector<WordWithCount> out) {
            for (String word : value.split("\\s")) {
              out.collect(new WordWithCount(word, 1L));
            }
          }
        })

        .keyBy("word")
        .timeWindow(Time.seconds(5))

        .reduce(new ReduceFunction<WordWithCount>() {
          @Override
          public WordWithCount reduce(WordWithCount a, WordWithCount b) {
            return new WordWithCount(a.word, a.count + b.count);
          }
        });

    // print the results with a single thread, rather than in parallel
    windowCounts.print().setParallelism(1);

    env.execute("Socket Window WordCount");
  }

  // ------------------------------------------------------------------------

  /**
   * Data type for words with count.
   */
  public static class WordWithCount {

    public String word;
    public long count;

    public WordWithCount() {}

    public WordWithCount(String word, long count) {
      this.word = word;
      this.count = count;
    }

    @Override
    public String toString() {
      return word + " : " + count;
    }
  }
}