Flink-1.9流计算开发：二、Map函数

public class StreamTest {
    private static final Logger LOG = LoggerFactory.getLogger(StreamTest.class);
    public static void main(String[] args) throws Exception {
        final StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
        String[] words = {"apple","orange","banana","watermelon"};
        //创建DataSource
        //根据给定的元素创建一个数据流，元素必须是相同的类型，比如全部为String，或者全部为int。
        DataStreamSource ds = env.fromElements(words);
        //Transformations
        //对DataStream应用一个Map转换。对DataStream中的每一个元素都会调用MapFunction接口的具体实现类。map方法仅仅只返回一个元素，这个flatMap不同
        DataStream map = ds.map(new MapFunction() {
            @Override
            public String map(String value) throws Exception {
                return value.toUpperCase();
            }
        });
        //sinks打印出信息
        //给DataStream添加一个Sinks
        map.addSink(new SinkFunction() {
            @Override
            public void invoke(String value) throws Exception {
                LOG.info(value);
            }
        });

        env.execute("Flink Streaming Java API Skeleton");
    }
}

15:03:05,937 INFO  fun.cosmozhu.session2.StreamTest                              - WATERMELON
15:03:05,937 INFO  fun.cosmozhu.session2.StreamTest                              - ORANGE
15:03:05,937 INFO  fun.cosmozhu.session2.StreamTest                              - APPLE
15:03:05,937 INFO  fun.cosmozhu.session2.StreamTest                              - BANANA