我知道这种问题已经回答了很多次，但我找不到我遇到的错误的答案::
我正在尝试将字符串 JSON 转换为 IntelliJ IDEA CE 中的案例类。
代码是这样的::
package com.netflix.ist.gbi.application
import scala.io.Source
import scala.collection.mutable._
import org.json4s._
//import org.json4s.DefaultFormats
import com.netflix.ist.gbi.model.EventPayloadIn
import org.json4s.jackson.JsonMethods._
object ObjDataArchival extends App{
val a : ListBuffer[String] = ListBuffer()
for (line Source.fromFile("/Users/sankar.biswas/Desktop/jsonFile.json").getLines) {
a.append(line)
jsonStrToMap(line)
}
def jsonStrToMap(jsonStr: String) : EventPayloadIn = {
implicit val formats : DefaultFormats.type = org.json4s.DefaultFormats
parse(jsonStr).extract[EventPayloadIn]
}
}
案例类在已导入的 scala 文件中定义。但是当我运行它时，我收到以下错误::
Exception in thread "main" java.lang.NoSuchMethodError: scala.Function0.$init$(Lscala/Function0;)V
at org.json4s.ThreadLocal.<init>(Formats.scala:348)
at org.json4s.DefaultFormats.$init$(Formats.scala:355)
at org.json4s.DefaultFormats$.<init>(Formats.scala:333)
at org.json4s.DefaultFormats$.<clinit>(Formats.scala)
at com.apple.ist.gbi.application.ObjDataArchival$.jsonStrToMap(ObjDataArchival.scala:21)
at com.apple.ist.gbi.application.ObjDataArchival$$anonfun$1.apply(ObjDataArchival.scala:16)
at com.apple.ist.gbi.application.ObjDataArchival$$anonfun$1.apply(ObjDataArchival.scala:13)
at scala.collection.Iterator$class.foreach(Iterator.scala:893)
at scala.collection.AbstractIterator.foreach(Iterator.scala:1336)
at com.apple.ist.gbi.application.ObjDataArchival$.delayedEndpoint$com$apple$ist$gbi$application$ObjDataArchival$1(ObjDataArchival.scala:13)
at com.apple.ist.gbi.application.ObjDataArchival$delayedInit$body.apply(ObjDataArchival.scala:10)
at scala.Function0$class.apply$mcV$sp(Function0.scala:34)
at scala.runtime.AbstractFunction0.apply$mcV$sp(AbstractFunction0.scala:12)
at scala.App$$anonfun$main$1.apply(App.scala:76)
at scala.App$$anonfun$main$1.apply(App.scala:76)
at scala.collection.immutable.List.foreach(List.scala:381)
at scala.collection.generic.TraversableForwarder$class.foreach(TraversableForwarder.scala:35)
at scala.App$class.main(App.scala:76)
at com.apple.ist.gbi.application.ObjDataArchival$.main(ObjDataArchival.scala:10)
at com.apple.ist.gbi.application.ObjDataArchival.main(ObjDataArchival.scala)
错误似乎在这一行::
implicit val formats : DefaultFormats.type = org.json4s.DefaultFormats
我尝试使用类似的行，例如 ::
implicit val formats = DefaultFormats
但无法以任何方式解决问题。
提前致谢！
像下面这样的东西可以工作。
import org.json4s._
import org.json4s.jackson.JsonMethods._
import scala.io.Source
object JSONParsing extends App {
implicit val formats = DefaultFormats // Brings in default date formats etc.
case class BookDetails(bookId: String, bookName: String, authorName: String, authorCountry: String)
for (line <- Source.fromFile("/Users/sankar.biswas/Desktop/jsonFile.json").getLines) {
val bookDetails = jsonStrToMap(line)
println(bookDetails)
}
def jsonStrToMap(jsonStr: String): BookDetails = {
parse(jsonStr).camelizeKeys.extract[BookDetails]
}
}
jsonFile文件内容：
{"book_id":"1","book_name":"Scala","author_name":"Edward","author_country":"Poland"}
{"book_id":"1","book_name":"Scala","author_name":"Edward","author_country":"Poland"}
{"book_id":"1","book_name":"Scala","author_name":"Edward","author_country":"Poland"}
{"book_id":"1","book_name":"Scala","author_name":"Edward","author_country":"Poland"}
更新 ：
生成.sbt
"org.json4s" %% "json4s-native" % "3.5.2",
"org.json4s" %% "json4s-jackson" % "3.6.0"
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我来说两句