flink java生成流式数据

写法比较套路，整体思路是：

1. 定义一个需要生成的数据类型
2. 实现SourceFunction接口的两个功能
3. 直接使用env.addSource()传入即可

import org.apache.flink.streaming.api.datastream.DataStreamSource;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.api.functions.source.SourceFunction;

import java.util.Random;

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

        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
        DataStreamSource sourceStream = env.addSource(new MyDataSource());
        env.setParallelism(1);
        sourceStream.print();
        env.execute();
    }

    private static class MyDataSource implements SourceFunction {
        // 定义标志位，用来控制数据的产生
        private boolean isRunning = true;
        private final Random random = new Random(0);

        @Override
        public void run(SourceContext ctx) throws Exception {
            while (isRunning) {
                ctx.collect(random.nextFloat());
                Thread.sleep(1000L); // 1s生成1个数据
            }
        }

        @Override
        public void cancel() {
            isRunning = false;
        }
    }
}