first Flink application , used to wordcount

SocketWindowWordCount.java

package myflink;

import org.apache.flink.api.common.functions.FlatMapFunction;
import org.apache.flink.api.java.tuple.Tuple2;
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;

public class SocketWindowWordCount {
	
	public static void main(String[] args) throws Exception {
		
		// 创建 execution environment
		final StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
		
		// 通过连接 socket 获取输入数据，这里连接到本地9000端口，如果9000端口已被占用，请换一个端口
		DataStream<String> text = env.socketTextStream("localhost", 9000, "\n");
		
		// 解析数据，按 word 分组，开窗，聚合
		DataStream<Tuple2<String, Integer>> windowCounts = text
				.flatMap(new FlatMapFunction<String, Tuple2<String, Integer>>() {
					@Override
					public void flatMap(String value, Collector<Tuple2<String, Integer>> out) {
						for (String word : value.split("\\s")) {
							out.collect(Tuple2.of(word, 1));
						}
					}
				})
				.keyBy(0)
				.timeWindow(Time.seconds(5))
				.sum(1);
		
		// 将结果打印到控制台，注意这里使用的是单线程打印，而非多线程
		windowCounts.print().setParallelism(1);
		// 新打开 Shell 执行: nc -lk 9000
		// 在Terminal 输入要统计的  文字流。 
		env.execute("Socket Window WordCount");
	}
}

WordCountExample.java

package myflink;


import org.apache.flink.api.common.functions.FlatMapFunction;
import org.apache.flink.api.java.DataSet;
import org.apache.flink.api.java.ExecutionEnvironment;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.util.Collector;

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

		final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
		
		DataSet<String> text = env.fromElements(
				"Who's there?",
				"I think I hear them. Stand, ho! Who's there?");
		
		DataSet<Tuple2<String, Integer>> wordCounts = text
				.flatMap(new LineSplitter())
				.groupBy(0)
				.sum(1);
		
		wordCounts.print();
	}
	
	public static class LineSplitter implements FlatMapFunction<String, Tuple2<String, Integer>> {
		@Override
		public void flatMap(String line, Collector<Tuple2<String, Integer>> out) {
			for (String word : line.split(" ")) {
				out.collect(new Tuple2<String, Integer>(word, 1));
			}
		}
	}
}