scala – saveTocassandra找不到参数rwf的隐含值

发布时间：2020-12-16 19:17:12 所属栏目：安全来源：网络整理

导读：我正在尝试使用spark scala在Cassandra数据库中保存数据集,但是在运行代码时遇到异常：使用链接： http://rustyrazorblade.com/2015/01/introduction-to-spark-cassandra/ error:could not find implicit value for parameter rwf: com.datastax.spark.conn

我正在尝试使用spark scala在Cassandra数据库中保存数据集,但是在运行代码时遇到异常：
使用链接： http://rustyrazorblade.com/2015/01/introduction-to-spark-cassandra/

error:

could not find implicit value for parameter rwf: com.datastax.spark.connector.writer.RowWriterFctory[FoodToUserIndex]
 food_index.saveToCassandra("tutorial","food_to_user_index")
                          ^

.scala

def main(args: Array[String]): Unit = {

val conf = new SparkConf(true)
  .set("spark.cassandra.connection.host","localhost")
  .set("spark.executor.memory","1g")
  .set("spark.cassandra.connection.native.port","9042")
val sc = new SparkContext(conf)


case class FoodToUserIndex(food: String,user: String)

val user_table = sc.cassandraTable[CassandraRow]("tutorial","user").select("favorite_food","name")

val food_index = user_table.map(r => new   FoodToUserIndex(r.getString("favorite_food"),r.getString("name")))
food_index.saveToCassandra("tutorial","food_to_user_index")}

build.sbt

name := "intro_to_spark"

version := "1.0"

scalaVersion := "2.11.2"

libraryDependencies += "org.apache.spark" %% "spark-core" % "1.2.0"

libraryDependencies += "com.datastax.spark" %% "spark-cassandra-connector" %  "1.2.0-rc3"

如果将scala和cassandra连接器的版本更改为2.10,1.1.0就可以了.但我需要使用scala 2.11：

scalaVersion := "2.10.4"

libraryDependencies += "org.apache.spark" %% "spark-core" % "1.2.0"

libraryDependencies += "com.datastax.spark" %% "spark-cassandra-connector" %   "1.1.0" withSources() withJavadoc()

解决方法

移动案例类FoodToUserIndex(food：String,user：String)在main函数之外应该解决问题.

（编辑：李大同）

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