如何从avro4s 3.0.4迁移到4.0.0-RC2

Question

如何从avro4s 3.0.4迁移到4.0.0-RC2？我有以下编译错误：

[error] /Users/nicolae.marasoiu/proj/data-availability-global-topic-conveyor/src/main/scala/com/ovoenergy/globaltopics/serdes/AvroFormatImplicits.scala:8:15: value const is not a member of object com.sksamuel.avro4s.SchemaFor
[error]     SchemaFor.const(new Schema.Parser().parse(getClass.getResourceAsStream(hasSchema.resourcePath)))
[error]               ^
[error] /Users/nicolae.marasoiu/proj/data-availability-global-topic-conveyor/src/main/scala/com/ovoenergy/globaltopics/serdes/AvroFormatImplicits.scala:11:26: not enough arguments for method apply: (implicit evidence$1: com.sksamuel.avro4s.Encoder[T], implicit evidence$2: com.sksamuel.avro4s.Decoder[T])com.sksamuel.avro4s.RecordFormat[T] in object RecordFormat.
[error] Unspecified value parameter evidence$2.
[error]     RecordFormat.apply[T](AvroSchema[T](readSchema))
[error]                          ^
[error] /Users/nicolae.marasoiu/proj/data-availability-global-topic-conveyor/src/main/scala/com/ovoenergy/globaltopics/serdes/SerdeProvider.scala:29:37: org.apache.avro.Schema does not take parameters
[error]     val schema = SchemaFor[T].schema(DefaultFieldMapper)
[error]                                     ^
[error] /Users/nicolae.marasoiu/proj/data-availability-global-topic-conveyor/src/main/scala/com/ovoenergy/globaltopics/serdes/SerdeProvider.scala:37:70: no arguments allowed for nullary method build: ()com.sksamuel.avro4s.AvroOutputStream[T]
[error]             val os     = AvroOutputStream.binary[T].to(output).build(schema)
[error]                                                                      ^
[error] four errors found
[error] (Compile / compileIncremental) Compilation failed
[error] Total time: 17 s, completed 28-Jul-2020 19:42:21
[IJ]sbt:global-topic-conveyor> 

Answer 1

首先，您可以随时关注avro4s github存储库中的更改。此外，您还可以看到在指定的版本之间所做的特定更改。

你没有附加任何源代码，所以我会努力解决你的失败，因为我可以从你的失败中理解它们。

1. SchemaFor.const在3.0.5版本中被删除。您可以在版本之间的差异中看到这一点。假设您有Schema s，并且到目前为止您启动了SchemaFor.const(s)，那么现在您需要启动它：SchemaFor(s)。将使用默认的fieldMapper。你可以在这里看到
2. RecordFormat不再接受参数。因此，假设您有一个在RecordFormat.apply[T](AvroSchema[T](readSchema))应用的类型T，您需要将其更改为：RecordFormat[T]
3. 与数字1非常相似。CCD_ 7被去除。相反，您可以执行以下操作：SchemaFor[T].schema。Schema不再接受参数，所以不能用括号来调用它
4. AvroOutputStream.build曾经将模式作为参数。它不再需要它了。您需要将AvroOutputStream.binary[T].to(output).build(schema)更改为：AvroOutputStream.binary[T].to(output).build()