重载的方法值适用于替代方案：答案

【问题标题】：Overloaded method value apply with alternatives:重载的方法值适用于替代方案：
【发布时间】：2017-12-20 19:05:52
【问题描述】：

我是 spark 新手，我试图为 json 数据定义架构，但在 (spark-shell,

<console>:28: error: overloaded method value apply with alternatives:
  (fields: Array[org.apache.spark.sql.types.StructField])org.apache.spark.sql.types.StructType <and>
  (fields: java.util.List[org.apache.spark.sql.types.StructField])org.apache.spark.sql.types.StructType <and>
  (fields: Seq[org.apache.spark.sql.types.StructField])org.apache.spark.sql.types.StructType
 cannot be applied to (org.apache.spark.sql.types.StructField, org.apache.spark.sql.types.StructField)
       val schema = StructType(Array(StructField("type", StructType(StructField("name", StringType,   true), StructField("version", StringType,   true)), true) :: StructField("value", StructType(StructField("answerBlacklistedEntities", StringType,   true) :: StructField("answerBlacklistedPhrase", StringType,   true) :: StructField("answerEntities", StringType,   true) :: StructField("answerText", StringType,   true) :: StructField("blacklistReason", StringType,   true) :: StructField("blacklistedDomains", StringType,   true) :: StructField("blacklistedEntities", ArrayType(StringType, true), true) :: StructField("customerId", StringType,   true) :: StructField("impolitePhrase", StringType,   true) :: StructField("isResponseBlacklisted", BooleanType,   true) :: StructField("queryString", StringType,   true) :: StructField("utteranceDomains", StringType,   true) :: StructField("utteranceEntities", ArrayType(StringType, true), true) :: StructField("utteranceId", StructType(StructField("identifier", StringType, true)), true)) :: Nil)))

谁能指导我这里发生了什么？ :) 非常感谢您的帮助！

【问题讨论】：

标签： scala apache-spark

【解决方案1】：

这是因为：

val schema = StructType(Array(StructField("type", 
   StructType(StructField("name", StringType,   true), ...))

您创建StructType 并将StructField 作为参数传递，而它应该是StructFields 的序列：

val schema = StructType(Array(StructField("type", 
   StructType(Array(StructField("name", StringType,   true), ...)) ...)

【讨论】：