from_json输出保存为null时，在模式中定义为Int为Spark Dataframe

Question

当使用from_json与Encoders创建的schema时，从case class但只使用DF，不使用DS，如下所示:

case class MyProducts(PRODUCT_ID: Option[String], DESCRIPTION: Option[String], PRICE: Option[Int], OLD_FIELD_1: Option[String]) 
val ProductsSchema = Encoders.product[MyProducts].schema
val df_products_output_final = df_products_output.withColumn("parsedProducts", from_json(col("afterImage"), ProductsSchema)) 

1. 当定义PRICE为Int时，我在字段中得到一个空值。
2. 当定义PRICE为String时，我在字段中得到一个字符串值。
3. Int的DF定义在DF模式中是正确的。

这里有什么问题?

代码:

import org.json4s._
import org.json4s.jackson.JsonMethods._
import spark.implicits._
import org.apache.spark.sql.functions.{col, lit, when, from_json, map_keys, map_values, regexp_replace, coalesce}
import org.apache.spark.sql.types.{MapType, StringType}
import org.apache.spark.sql.Encoders
import org.apache.spark.sql.types.{MapType, StringType, StructType, IntegerType}
case class MyMeta(op: String, table: String)
val metaSchema = Encoders.product[MyMeta].schema
case class MySales(NUM: Option[Integer], PRODUCT_ID: Option[String], DESCRIPTION: Option[String], OLD_FIELD_1: Option[String]) 
val salesSchema = Encoders.product[MySales].schema
case class MyProducts(PRODUCT_ID: Option[String], DESCRIPTION: Option[String], PRICE: Option[Int], OLD_FIELD_1: Option[String]) 
val ProductsSchema = Encoders.product[MyProducts].schema
def getAfterImage (op: String, data: String, key: String, jsonOLD_TABLE_FIELDS: String) : String = {   
val jsonOLD_FIELDS = parse(jsonOLD_TABLE_FIELDS)   
val jsonData = parse(data)                         
val jsonKey = parse(key)                           

op match {
case "ins" =>
return(compact(render(jsonData merge jsonOLD_FIELDS)))
case _ => 
val Diff(changed, added, deleted) = jsonKey diff jsonData
return(compact(render(changed merge deleted merge jsonOLD_FIELDS)))
}
}
val afterImage = spark.udf.register("callUDFAI", getAfterImage _)
val path = "/FileStore/tables/json_0006_file.txt"  
val df = spark.read.text(path)  // String.
val df2 = df.withColumn("value", from_json(col("value"), MapType(StringType, StringType)))    
val df3 = df2.select(map_values(col("value")))  
val df4 = df3.select($"map_values(value)"(0).as("meta"), $"map_values(value)"(1).as("data"), $"map_values(value)"(2).as("key")).withColumn("parsedMeta", from_json(col("meta"), metaSchema)).drop("meta").select(col("parsedMeta.*"), col("data"), col("key")).withColumn("key2", coalesce(col("key"), lit(""" { "DUMMY_FIELD_XXX": ""} """) )).toDF().cache()
// DF at this stage, not a DF.
val df_sales    = df4.filter('table === "BILL.SALES") 
val df_products = df4.filter('table === "BILL.PRODUCTS")
val df_sales_output = df_sales.withColumn("afterImage", afterImage(col("op"), col("data"), col("key2") , lit(""" { "OLD_FIELD_1": ""} """)))
.select("afterImage") 
val df_products_output = df_products.withColumn("afterImage", afterImage(col("op"), col("data"), col("key2") , lit(""" { "OLD_FIELD_A":"", "OLD_FIELD_B":""} """)))
.select("afterImage")                          
val df_sales_output_final = df_sales_output.withColumn("parsedSales", from_json(col("afterImage"), salesSchema)) 
df_products_output_final.show(false)
df_products_output_final.printSchema()

Answer 1

PRICE字段值周围的引号会把这搞砸。

如果你改变了输入数据

{ "meta":{ "op":"upd", "table":"BILL.PRODUCTS" }, "data":{ "DESCRIPTION":"XXX" }, "key":{ "PRODUCT_ID":"230117", "DESCRIPTION":"Hamsberry vintage tee, cherry", "PRICE":"4099" }}
{ "meta":{ "op":"upd", "table":"BILL.PRODUCTS" }, "data":{ "PRICE":"4000" }, "key":{ "PRODUCT_ID":"230117", "DESCRIPTION":"Hamsberry vintage tee, cherry", "PRICE":"3599" }} 

{ "meta":{ "op":"upd", "table":"BILL.PRODUCTS" }, "data":{ "DESCRIPTION":"XXX" }, "key":{ "PRODUCT_ID":"230117", "DESCRIPTION":"Hamsberry vintage tee, cherry", "PRICE":4099 }}
{ "meta":{ "op":"upd", "table":"BILL.PRODUCTS" }, "data":{ "PRICE":4000 }, "key":{ "PRODUCT_ID":"230117", "DESCRIPTION":"Hamsberry vintage tee, cherry", "PRICE":3599 }} 

(区别只是PRICE值周围的引号)。

然后从脚本中得到如下输出:

+--------------------------------------------------------------------------------------------------------------------+---------------------------------------------------+
|afterImage                                                                                                          |parsedProducts                                     |
+--------------------------------------------------------------------------------------------------------------------+---------------------------------------------------+
|{"DESCRIPTION":"XXX","PRODUCT_ID":"230117","PRICE":4099,"OLD_FIELD_A":"","OLD_FIELD_B":""}                          |{230117, XXX, 4099, null}                          |
|{"PRICE":4000,"PRODUCT_ID":"230117","DESCRIPTION":"Hamsberry vintage tee, cherry","OLD_FIELD_A":"","OLD_FIELD_B":""}|{230117, Hamsberry vintage tee, cherry, 4000, null}|
+--------------------------------------------------------------------------------------------------------------------+---------------------------------------------------+
root
|-- afterImage: string (nullable = true)
|-- parsedProducts: struct (nullable = true)
|    |-- PRODUCT_ID: string (nullable = true)
|    |-- DESCRIPTION: string (nullable = true)
|    |-- PRICE: integer (nullable = true)
|    |-- OLD_FIELD_1: string (nullable = true)

不再有PRICE的null值了!!