简介

只要实现 SourceFunction 接口对应的方法就可以自定义数据源
1.创建环境

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

        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();

        DataStreamSource<SensorReading> streamSource = env.addSource(new MySensorSource());

        streamSource.print();

        env.execute();

    }

2.实现 SourceFunction 接口

 public static class MySensorSource implements SourceFunction<SensorReading> {

        //定义一个标识位用来控制数据
        private boolean running = true;
        //定义一个随机数发生器
        Random random = new Random();

        public void run(SourceContext<SensorReading> ctx) throws Exception {

            //设置10个传感器的初识温度
            HashMap<String, Double> sensorTempMap = new HashMap<String, Double>();
            for (int i = 0; i < 10; i++) {
                sensorTempMap.put("sensor_" + (i + 1), 60 + random.nextGaussian() * 20);
            }

            while (running) {

                for(String sensorId : sensorTempMap.keySet()){
                    //在当前的温度基础上随机波动
                    Double newtemp = sensorTempMap.get(sensorId) + random.nextGaussian();

                    sensorTempMap.put(sensorId,newtemp);

                    ctx.collect(new SensorReading(sensorId,System.currentTimeMillis(),newtemp));
                }
                //控制输出频率
                Thread.sleep(1000L);
            }

        }

        public void cancel() {
            running = false;
        }
    }