我是nifi的新手，在我的例子中，必须使用kafka的json主题，并希望将其转换为csv文件，在该文件中，我只需要选择几个标量和一些嵌套字段。
我需要做以下事情：

Consume topic - Done
 Json to CSV
 Include header in the CSV file
 Merge into single file (if its split)
 Give a proper filename with date

点击以下链接：https://community.hortonworks.com/articles/64069/converting-a-large-json-file-into-csv.html
但不确定这是否是正确的方法，也不知道如何制作单个文件。我正在使用 NiFi (1.8) and schema is stored in Confluent Schema Registry json示例：

{
  "type" : "record",
  "name" : "Customer",
  "namespace" : "namespace1"
  "fields" : [ {
    "name" : "header",
    "type" : {
      "type" : "record",
      "name" : "CustomerDetails",
      "namespace" : "namespace1"
      "fields" : [ {
        "name" : "Id",
        "type" : "string"
      }, {
        "name" : "name",
        "type" : "string"
      }, {
        "name" : "age",
        "type" : [ "null", "int" ],
        "default" : null
      }, {
        "name" : "comm",
        "type" : [ "null", "int" ],
        "default" : null
      } ]
    },
    "doc" : ""
  }, {
    "name" : "data",
    "type" : {
      "type" : "record",
      "name" : "CustomerData"
      "fields" : [ {
        "name" : "tags",
        "type" : {
          "type" : "map",
          "values" : "string"
        }
      }, {
        "name" : "data",
        "type" : [ "null", "bytes" ]
        "default" : null
      } ]
    },
    "doc" : ""
  } ]
}

请引导我。