使用 play Json 库（或任何其他建议）在多级数组上查找 JsLookup

Question

我的函数正在接收一个JsValue，现在这个json有列表，这个列表元素也可以是列表，例如：

{
  "firstName": "Elon",
  "lastName": "Musk",
  "companies": [
    {
      "name": "Tesla",
      "city": "San Francisco",
      "offices": ["sf", "ny"],
      "management": {
        "loscation": "New York",
        "boardMembers": [
          {
            "name": "John",
            "age": 45
          },
          {
            "name": "Mike",
            "age": 55
          },
          {
            "name": "Rebecca",
            "age": 35
          }
        ]
      }
    },
    {
      "name": "SpaceX",
      "city": "San Francisco",
      "offices": ["la", "ta"],
      "management": {
        "loscation": "San Mateo",
        "boardMembers": [
          {
            "name": "Lisa",
            "age": 45
          },
          {
            "name": "Dan",
            "age": 55
          },
          {
            "name": "Henry",
            "age": 35
          }
        ]
      }
    }
  ]
}

所以一个公司有管理对象，有boardMembers列表。

我的函数正在接收此元素的路径，例如：

companies[*].management.boardMembers[*].name

我希望它 return 包含此对象的所有元素的列表，因此结果将是：

["John", "Mike", "Rebecca", "Lisa", "Dan", "Henry"]

有点复杂，但我想 play.api.libs.json._ 可能会有一些可以提供帮助的功能。

考虑过拆分它 pathStr.split("(\[\*]\.|\[\*])").toList 然后迭代以获取所有元素一些如何和 return JsLookupResult 但不确定如何。

澄清一下：

我的方法将接收 2 个参数，JsValue 和字符串形式的路径 def myFunc(json: JsValue, path: String)

每次我调用myFunc它都会收到不同的路径，我不确定只有在调用myFunc之后它才会是什么。

Answer 1

正如您在文档中看到的那样，您可以使用 Reads 类型类来定义从 JSON.

解码类型的方式

import play.api.libs.json._

val input = """{
  "firstName": "Elon",
  "lastName": "Musk",
  "companies": [
    {
      "name": "Tesla",
      "city": "San Francisco",
      "offices": ["sf","ny"],
      "management": {
        "loscation": "New York",
        "boardMembers": [
          {
            "name": "John",
            "age": 45
          },
          {
            "name": "Mike",
            "age": 55
          },
          {
            "name": "Rebecca",
            "age": 35
          }
        ]
      }
    },
    {
      "name": "SpaceX",
      "city": "San Francisco",
      "offices": ["la","ta"],
      "management": {
        "loscation": "San Mateo",
        "boardMembers": [
          {
            "name": "Lisa",
            "age": 45
          },
          {
            "name": "Dan",
            "age": 55
          },
          {
            "name": "Henry",
            "age": 35
          }
        ]
      }
    }
  ]
}"""

val json = Json.parse(input)

// ---

case class BoardMember(name: String, age: Int)

implicit val br: Reads[BoardMember] = Json.reads

case class Company(boardMembers: Seq[BoardMember])

implicit val cr: Reads[Company] = Reads {
  case obj @ JsObject(_) =>
    (obj \ "management" \ "boardMembers").validate[Seq[BoardMember]].map {
      Company(_)
    }

  case _ =>
    JsError("error.obj.expected")
}

val reads = Reads[Seq[String]] {
  case obj @ JsObject(_) =>
    (obj \ "companies").validate[Seq[Company]].map {
      _.flatMap(_.boardMembers.map(_.name))
    }

  case _ =>
    JsError("error.obj.expected")
}

// ---

json.validate(reads)
//  play.api.libs.json.JsResult[Seq[String]] = JsSuccess(Vector(John, Mike, Rebecca, Lisa, Dan, Henry),)

Answer 2

你可以这样做：

val jsPath = JsPath \ "companies" \ "management" \ "boardMembers" \ "name"
val result = jsPath(Json.parse(input))
println(result)

这将打印预期的输出。请参阅 Scastie 示例。

请注意\和\的区别：

\寻找直系子代
\ 查找递归子项

要实现 myFunc，您可以尝试这样的操作：

def findAllValuesAtPath(jsValue: JsValue, path: String): List[JsValue] = {
  val jsPath = JsPath(path
    .split("\[\*]\.")
    .flatMap(s => s.split("\.")
      .map(RecursiveSearch)
    ).toList)
  println(jsPath.path)
  jsPath(jsValue)
}

Here 是另一个 scastie。

使用 play Json 库（或任何其他建议）在多级数组上查找 JsLookup

JsLookup on multiple level array using play Json library (or any other suggestion)

scala

playframework

playframework-2.0

playframework-2.2

play-json