Apache Beam动态窗口写入用defaultNaming遇NetBeans语法错误求助

Let's break down what's causing that syntax error in your withNaming line and fix it:

The Root Cause #

The error is happening because you're trying to call defaultNaming() without properly referencing its containing class. In Apache Beam, defaultNaming is a static method belonging to FileIO.Write, so you need to qualify it with the full class path to resolve it correctly.

Corrected Code #

Here's the fixed version of your method:

static void applyWindowedWrite(PCollection<String> stream) {
 stream.apply(
  FileIO.<String, String>writeDynamic()
   .by(Event::getKey)
   .via(TextIO.sink())
   .to("gs://some_bucket/events/")
   .withNaming(key -> FileIO.Write.defaultNaming(key, ".json")));
}

Additional Checks (Just to Be Safe) #

• Make sure you have the correct import for FileIO:

  import org.apache.beam.sdk.io.FileIO;
  

• If you're using an older Beam version, double-check the defaultNaming method signature—some earlier releases used slightly different parameter ordering, but your suffix choice of .json is perfectly valid for the current standard signature.

Why This Works #

By adding FileIO.Write. before defaultNaming, you're telling the compiler exactly where to find that static method. The lambda key -> FileIO.Write.defaultNaming(key, ".json") correctly maps each event key to a unique file naming scheme, which is exactly what writeDynamic() expects for partitioning your output files by key.

内容的提问来源于stack exchange，提问作者ljhenne