flink 不在 std 输出中打印对象 [英] flink don't print the object in the std output

问题描述

我正在 flink 中做一个简单的程序，但它不会在 std 输出中打印任何字符串.我已经尝试在流上使用 print() 方法，并在其结果上使用 reduce 函数和 after print() 方法.这是一个代码:

i'm doing a simple program in flink, but it doesn't print any string in the std output. I have tried both using a print() method on the stream and using a reduce function and after print() method on its result. this is a code:

公共类 StreamingJob {

public class StreamingJob {

public static void main(String[] args) throws Exception {
    final StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
    env.enableCheckpointing(10000);
    env.setStreamTimeCharacteristic(TimeCharacteristic.EventTime);
    env.getConfig().setAutoWatermarkInterval(200L);
    List<Oggetto> objects = produciValori();
    DataStream<Oggetto> stream = env.fromCollection(objects);
    stream./*
    timeWindowAll(Time.seconds(5)).reduce(new Reduce()).*/
    print();
    env.execute("Flink Streaming Java Quickstart Mio");
}

private static List<Oggetto> produciValori() {
    List<Oggetto> objects = new ArrayList<>();
    int prop1 = 0;
    int prop2 = 1000;
    String stringa1 = "stringa1: " + prop1;
    String stringa2 = "stringa2: " + prop2;
    for (int i = 0; i < 1000; i++) {
        prop1 = prop1 + 1;
        prop2 = prop2 + 1;
        stringa1 = "stringa1: " + prop1;
        stringa2 = "stringa2: " + prop2;
        Oggetto o = new Oggetto(prop1, prop2, stringa1, stringa2);
        objects.add(o);
    }
    return objects;
}

private static class Reduce implements org.apache.flink.api.common.functions.ReduceFunction<Oggetto> {
    @Override
    public Oggetto reduce(Oggetto oggetto, Oggetto t1) throws Exception {
        if (oggetto.getPropInt1() <= t1.getPropInt1()){
            return oggetto;
        }else {
            return t1;
        }
    }
}

}

推荐答案

所以每当你使用 println() 或 print() 打印流数据/对象时，它实际上打印在控制台上.

So whenever you use println() or print() to print the stream data/object, it actually prints on the console.

• 当您在本地 IDE 中执行代码时，它会在 IDE 控制台 中打印流数据/对象，但
• 当您将代码部署为 Flink Job 时，您可以在 Flink 目录中的 .out 文件中看到打印的输出.在下图中，您可以看到 flink-keshavlodhi-taskexecutor-0-Keshavs-MacBook-Pro.local.out 文件.

• When you execute code in local IDE it prints the stream data/object in IDE console but
• When you deploy the code as a Flink Job you can see the printed output in .out file in your Flink directory. In the below image you can see flink-keshavlodhi-taskexecutor-0-Keshavs-MacBook-Pro.local.out file.

您可以在系统中找到 Flink 日志目录，您将 Flink tar 文件解压到该目录中.例如

You can find Flink log directory in your system where you have extracted the Flink tar file. e.g

/Users/keshavlodhi/softwares/flink-1.10.0/log/

注意:每当您使用任何 logger API 打印该时间时，您都可以在 .log 文件中找到您的流数据/对象.

Note: Whenever you use any logger APIs to print that time you can find your stream data/object in .log files.

这篇关于flink 不在 std 输出中打印对象的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！