使用 json4s 的 JSON 非漂亮渲染

Question

下面的代码在我想要 JSON 输出的地方运行良好。嗯，差不多。请参阅下面的代码。

它返回：

+--------------------------------------------------------------------------------------------------------+
|afterImage                                                                                              |
+--------------------------------------------------------------------------------------------------------+
|{\n  "PRICE" : "3599",\n  "PRODUCT_ID" : "230117",\n  "DESCRIPTION" : "Hamsberry vintage tee, cherry"\n}|
|{\n  "PRICE" : "4000",\n  "PRODUCT_ID" : "230117",\n  "DESCRIPTION" : "Hamsberry vintage tee, cherry"\n}|
|{\n  "NUM" : "20",\n  "PRODUCT_ID" : "230117",\n  "DESCRIPTION" : "Hamsberry vintage tee, cherry"\n}    |
+--------------------------------------------------------------------------------------------------------+

但我想删除

\n

。我可以编写代码，但我想知道是否有更好的方法可以不使用 JACKSON 或其他 JACKSON 方法来执行此操作。当然

regexp_replace

是一个选项。

我查看了 Spark dataframe to jackson json in scala，但这不是我正在考虑的方法。我最喜欢

Diff

和

pretty

。

import org.json4s._
import org.json4s.jackson._

import spark.implicits._
import org.apache.spark.sql.functions.{col, lit, when, from_json, map_keys, map_values}
import org.apache.spark.sql.types.{MapType, StringType}

val path = "/FileStore/tables/json_0002C_file.txt"  
val df = spark.read.text(path)  // String
val df2 = df.withColumn("value", from_json(col("value"), MapType(StringType, StringType)))  // Always 3 elements. Plus add in one later potentially. 
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"))

def getAfterImage = (data: String, key: String) => {
  val jsonData = parse(data) 
  val jsonKey  = parse(key)
  val Diff(changed, added, deleted) = jsonKey diff jsonData
  val afterImage = changed merge deleted
  pretty(render(afterImage))  // String, need to add the dummy missing columns, for those that have been dropped but...
}

val afterImage = spark.udf.register("callUDFAI", getAfterImage)
val df5 = df4.withColumn("afterImage", afterImage(col("data"), col("key"))).select("afterImage")//.show(false)
df5.show(false)
df5.printSchema()

ANSWER 清楚并正式回答，保留原样以帮助他人。