小编cod*_*ato的帖子

我不了解动态绑定和适当覆盖的概念：

这是一些代码：

class Cake {
    public void taste (Cake c) {
        System.out.println("In taste of Cake class");
    }
}

class ChocolateCake extends Cake {
    public void taste(Cake c) {
        System.out.println("In taste (Cake version) of ChocolateCake class");
    }
    public void taste(ChocolateCake cc) {
        System.out.println("In taste (ChocolateCake version) of ChocolateCake class");
    }
}


public static void main(String[] args)
{
    ChocolateCake cc = new ChocolateCake();
    Cake c = new ChocolateCake();
    Cake c1 = new Cake();
    Cake c2 = new ChocolateCake();

    c1.taste(cc);
    c1.taste(c);

    c2.taste(cc);
    c2.taste(c); …

我正在使用该telegraf软件包开发电报机器人。（版本 4.1.1）

一切正常，直到我开始使用来自 Telegraf 包的更多模块，如Extra和mark-up。

我开始收到此错误：

internal/modules/cjs/loader.js:800
    throw err;
    ^
Error: Cannot find module 'typegram/callback'
Require stack:
- C:\gitprojects\bot\node_modules\telegraf\lib\telegram-types.js
- C:\gitprojects\bot\node_modules\telegraf\lib\context.js
- C:\gitprojects\bot\node_modules\telegraf\lib\composer.js
- C:\gitprojects\bot\node_modules\telegraf\lib\telegraf.js
- C:\gitprojects\bot\node_modules\telegraf\lib\index.js
- C:\gitprojects\bot\index.js
?[90m    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:797:15)?[39m
?[90m    at Function.Module._load (internal/modules/cjs/loader.js:690:27)?[39m
?[90m    at Module.require (internal/modules/cjs/loader.js:852:19)?[39m
?[90m    at require (internal/modules/cjs/helpers.js:74:18)?[39m
    at Object.<anonymous> (C:\gitprojects\bot\node_modules\?[4mtelegraf?[24m\lib\telegram-types.js:16:14)
?[90m    at Module._compile (internal/modules/cjs/loader.js:959:30)?[39m
?[90m    at Object.Module._extensions..js (internal/modules/cjs/loader.js:995:10)?[39m
?[90m    at Module.load (internal/modules/cjs/loader.js:815:32)?[39m
?[90m    at Function.Module._load (internal/modules/cjs/loader.js:727:14)?[39m
?[90m    at Module.require (internal/modules/cjs/loader.js:852:19)?[39m {
  code: ?[32m'MODULE_NOT_FOUND'?[39m,
  requireStack: [
    ?[32m'C:\\gitprojects\\bot\\node_modules\\telegraf\\lib\\telegram-types.js'?[39m, …

我使用结构化流来读取kafka主题，使用spark 2.4和scala 2.12

我使用检查点来使我的查询具有容错能力。

但是，每次我开始查询时，它都会跳转到当前偏移量，而不会在连接到主题之前读取现有数据。

我缺少 kafka 流的配置吗？

读：

 val df = spark.readStream
    .format("kafka")
    .option("kafka.bootstrap.servers", "localhost:9092")
    .option("subscribe", "test")
    .option("maxOffsetsPerTrigger","1")
    .option("startingOffset","earliest")
    .option("auto.offset.reset","earliest")
    .load()
val msg = df.select($"value" cast "string", $"topic", $"partition", $"offset")

写：

val query= msg.writeStream
    .foreachBatch(
      (dfbatch: Dataset[Row], batchid: Long) =>
      {
      println(s"IM AT BATCH ID: $batchid")
      dfbatch.show()
      dfbatch.write.csv(s"s3a://abucket/$param")
      }
    )
      .option("checkpointLocation","s3a://checkpoint/")
      .trigger(Trigger.ProcessingTime("10 seconds"))
      .format("console")
      .start()

 query.awaitTermination()

编辑：

这是我清空检查点目录后的日志：

0/07/11 18:15:16 INFO CheckpointFileManager: Writing atomically to s3a://checkpoint/metadata using temp file s3a://checkpoint/.metadata.304a751a-68b7-4b8d-858c-3aa5df272db4.tmp
20/07/11 18:15:17 INFO CheckpointFileManager: Renamed temp …