Flink学习5---DataStream之DataSource API (三)基于集合的fromCollection

    技术2024-12-01  14

    fromCollection 可直接从集合中读取数据作为流,由于集合是有界的,所以该数据流有界,读完之后程序会自动退出。

    是非并行的DataSource,主要用于测试。

    import org.apache.flink.streaming.api.datastream.DataStreamSource; import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment; import java.util.Arrays; public class FromCollectionReview { public static void main(String[] args) throws Exception{ // 1.获取flink流计算的运行环境 StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment(); // 2.从collection读取数据 // DataStreamSource<Integer> nums = env.fromElements(1,2,3,4,5,6,7,8,9);; DataStreamSource<Integer> nums = env.fromCollection(Arrays.asList(1,2,3,4,5,6,7,8,9)); //3.调用Sink nums.print(); //4.启动流计算 env.execute("FromCollectionReview"); }

    运行结果如下:

    Processed: 0.018, SQL: 9