java.lang.IllegalStateException : Unable to return a default Coder in dataflow 2. X

Question

我在数据流 2.1 SDK 中有一个简单的管道。它从 pubsub 读取数据，然后对其应用 DoFn。

PCollection<MyClass> e = streamData.apply("ToE", ParDo.of(new MyDoFNClass()));

在此管道上出现以下错误:

java.lang.IllegalStateException: Unable to return a default Coder for ToEvents/ParMultiDo(MyDoFNClass).out0 [PCollection]. Correct one of the following root causes: No Coder has been manually specified; you may do so using .setCoder(). Inferring a Coder from the CoderRegistry failed: Unable to provide a Coder for com.X.X.model.MyClass.

MyDoFn 类如下:

@DefaultCoder(AvroCoder.class)

public class MyClass{

    public long id;
    public HashMap<String,HashSet<String>> a;

    @SerializedName("a")
    public Integer Id;
    @SerializedName("ae")
    public String ae;
}

Answer 1

找到解决方案只需要将 implements Serializable 添加到 MyClass

@DefaultCoder(AvroCoder.class)

public class MyClass implements Serializable {

public long id;
public HashMap<String,HashSet<String>> a;

@SerializedName("a")
public Integer Id;
@SerializedName("ae")
public String ae;
}