Apache Flink教程----2.本地开发

<dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-clients_2.12</artifactId>
            <version>1.8.0</version>
</dependency>

public class FlinkDemo {
    public static void main(String[] args) throws Exception {
        final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
        // get input data
        DataSet<String> text = env.fromElements(
                "To be, or not to be,--that is the question:--",
                "Whether 'tis nobler in the mind to suffer",
                "The slings and arrows of outrageous fortune",
                "Or to take arms against a sea of troubles,"
        );
        DataSet<Tuple2<String, Integer>> counts =
                // split up the lines in pairs (2-tuples) containing: (word,1)
                text.flatMap(new LineSplitter())
                        // group by the tuple field "0" and sum up tuple field "1"
                        .groupBy(0) //(i,1) (am,1) (chinese,1)
                        .sum(1);
        // execute and print result
        counts.print();
    }
    public static final class LineSplitter implements FlatMapFunction<String, Tuple2<String, Integer>> {
        public void flatMap(String value, Collector<Tuple2<String, Integer>> out) {
            // normalize and split the line
            String[] tokens = value.toLowerCase().split("\\W+");
            // emit the pairs
            for (String token : tokens) {
                if (token.length() > 0) {
                    out.collect(new Tuple2<String, Integer>(token, 1));
                }
            }
        }
    }
}