具有通用类型问题的Avro序列化 [英] Avro serialization with generic type issue

问题描述

我需要在Scala中编写一个函数，该函数返回一个用AvroOutputStream序列化的字节数组，但是在Scala中，我无法获取输入中传递的通用对象的类. 这是我的util类:

I need to write a function in Scala that returns an Array of byte serializated with AvroOutputStream, but in scala i can't get the class of the generic object i'm passing in input. Here is my util class:

class AvroUtils {

    def createByteArray[T](obj: T): Array[Byte] = {
        val byteArrayStream = new ByteArrayOutputStream()
        val output = AvroOutputStream.binary[T](byteArrayStream)
        output.write(obj)
        output.close()
        byteArrayStream.toByteArray()
    }
}

您可以看到您是否要测试此代码，因为AvroOutputStream无法识别T类，因此它无法为其生成模式. 希望能对您有所帮助！谢谢

As you can see if tou test this code is that AvroOutputStream can't recognize the T class so it can't generate a schema for it. Hope you can help! thanks

PS:已经尝试使用TypeTag和ClassTag，但没有任何效果.

PS: Already tried with TypeTag and ClassTag, nothing works.

推荐答案

您需要为T添加适当的隐式，即SchemaFor和ToRecord:

You need to add the proper implicits for T, namely SchemaFor and ToRecord:

def createByteArray[T : SchemaFor : ToRecord](obj: T): Array[Byte] = {
  val byteArrayStream = new ByteArrayOutputStream()
  val output = AvroOutputStream.binary[T](byteArrayStream)
  output.write(obj)
  output.close()
  byteArrayStream.toByteArray()
}

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