Flink如何读取数据源

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从集合中读取

    private static void radFromCollection(String[] args) throws Exception {        //将参数转成对象        MultipleParameterTool params = MultipleParameterTool.fromArgs(args);        //创建批处理执行环境//        ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();        //创建流程处理        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();        //设置每个算子的的并行度，默认为cup核数（测试环境下）        env.setParallelism(2);        //设置最大并行度        env.setMaxParallelism(6);        //从集合中读取        List collectionData = Arrays.asList("a", "b", "c", "d");        DataStreamSource dataStreamSource = env.fromCollection(collectionData);        //从数组中读取        // env.fromElements("a", "b", "c", "d");        dataStreamSource.print(); //dataStreamSource.addSink(new PrintSinkFunction<>());        env.execute();    }

从文件中读取

    StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();        DataStreamSource dataStreamSource = env.readTextFile("E:\\GIT\\flink-learn\\flink1\\word.txt", "utf-8");        dataStreamSource.print();        env.execute();

从kafka 中读取

StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();        Properties properties = new Properties();        properties.put("bootstrap.servers", "10.1.5.130:9092");        properties.put("zookeeper.connect", "10.2.5.135:2181");        properties.put("group.id", "my-flink");        properties.put("auto.offset.reset", "latest");        properties.put("key.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");        properties.put("value.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");        FlinkKafkaConsumer010 kafkaConsumer010 = new FlinkKafkaConsumer010<>(                "flink",// topic                new SimpleStringSchema(),                properties        );        DataStreamSource dataStreamSource = env.addSource(kafkaConsumer010);        dataStreamSource.print();        env.execute();

从自定义Source 中读取

• 实现 org.apache.flink.streaming.api.functions.source.SourceFunction

 public static final class MyDataSource implements SourceFunction {        private Boolean running = true;        @Override        public void run(SourceContext sourceContext) throws Exception {            Random random = new Random();            while (running) {                double data = random.nextDouble() * 100;                sourceContext.collectWithTimestamp(String.valueOf(data), System.currentTimeMillis());                TimeUnit.SECONDS.sleep(1);            }        }        @Override        public void cancel() {            this.running = false;        }    }

  StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();        DataStreamSource dataStreamSource = env.addSource(new MyDataSource());        dataStreamSource.print();        env.execute();

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