使用 Play JSON 查询并查找 JSON 元素值的路径

Question

我正在将 Play Framework 与 Scala 结合使用。对于上游服务器返回的 JSON，我有以下结构。这只是一个代表

{
  "key": "some-key",
  "suspendData": {
    "d": [
      [
        "arbitrary-objects/strings"
      ],
      [
        "random-value",
        [
          "arbitrary-objects/strings"
        ],
        [
          [
            "value1",
            "important-item",
            [
              "important-key-1"
            ],
            "arbitrary-values/objects"
          ],
          [
            "value2",
            "important-item-2",
            [
              "important-key-2"
            ]
          ]
        ]
      ]
    ]
  }
}

我所知道的唯一事实是数据将位于 $.suspendData.d[1] 内的某处。我知道我要搜索的值是 important-key-1。该值可以嵌套得更深，也可以位于 `d[1] 中的不同索引上。我该如何解决查找是否

的问题

从上游服务器获取的JSON中存在密钥
找到key的路径，所以我可以根据相同的路径找到其他的key。这是一个反向查找问题。

目前只能想到获取$.suspendData.d[1]然后循环查找是否存在这样的属性。同样，我找不到通过 JsPath 执行此操作的正确方法。我知道 JsonPath 等效项，但无法通过现有的 Play JSON 支持找到正确的方法。

Answer 1

您可以使用 JsValue 上定义的 \ 方法并导航到 Json

中您想要的位置

为了得到你想做的事((json \ "suspendData") \ "d")(1)

这是 REPL 相同

的输出

scala> val json = Json.parse(str) 
json: JsValue = {"key":"some-key","suspendData":{"d":[["arbitrary-objects/strings"],["random-value",["arbitrary-objects/strings"],[["value1","important-item",["important-key-1"],"arbitrary-values/objects"],["value2","important-item-2",["important-key-2"]]]]]}}

scala> ((json \ "suspendData") \ "d")(1) 
res32: JsLookupResult = JsDefined(
  ["random-value",["arbitrary-objects/strings"],[["value1","important-item",["important-key-1"],"arbitrary-values/objects"],["value2","important-item-2",["important-key-2"]]]]
)

scala> val json = Json.parse(str) 
json: JsValue = {"key":"some-key","suspendData":{"d":[["arbitrary-objects/strings"],["random-value",["arbitrary-objects/strings"],[["value1","important-item",["important-key-1"],"arbitrary-values/objects"],["value2","important-item-2",["important-key-2"]]]]]}}

scala> (json \ "suspendData") 
res34: JsLookupResult = JsDefined(
  {"d":[["arbitrary-objects/strings"],["random-value",["arbitrary-objects/strings"],[["value1","important-item",["important-key-1"],"arbitrary-values/objects"],["value2","important-item-2",["important-key-2"]]]]]}
)

scala> (json \ "suspendData") \ "d" 
res35: JsLookupResult = JsDefined(
  [["arbitrary-objects/strings"],["random-value",["arbitrary-objects/strings"],[["value1","important-item",["important-key-1"],"arbitrary-values/objects"],["value2","important-item-2",["important-key-2"]]]]]
)

scala> ((json \ "suspendData") \ "d")(0) 
res36: JsLookupResult = JsDefined(["arbitrary-objects/strings"])

scala> ((json \ "suspendData") \ "d")(1) 
res37: JsLookupResult = JsDefined(
  ["random-value",["arbitrary-objects/strings"],[["value1","important-item",["important-key-1"],"arbitrary-values/objects"],["value2","important-item-2",["important-key-2"]]]]
)

Answer 2

简单的递归，可能不是那么有效，但有效：

def findPath(key: String, path: JsPath, xs: JsValue): Option[JsPath] = {
  xs match {
    case o:JsObject =>
      var res: Option[JsPath] = None
      val it = o.fields.iterator
      while (res.isEmpty && it.hasNext) {
        val e = it.next()
        res = findPath(key, path \ (e._1), e._2)
      }
      res
    case JsString(x) if x==key => 
      Some(path)
    case JsArray(x) =>
      var res: Option[JsPath] = None
      val it = x.zipWithIndex.iterator
      while (res.isEmpty && it.hasNext) {
        val e = it.next()
        res = findPath(key, path(e._2), e._1)
      }
      res
    case _ => None
  }
}

findPath("important-key-1", __, j)
findPath("important-key-2", __, j)
findPath("important-key-3", __, j)
findPath("some-key", __, j)

scala> res62: Option[play.api.libs.json.JsPath] = Some(/suspendData/d(1)(2)(0)(2)(0))

scala> res63: Option[play.api.libs.json.JsPath] = Some(/suspendData/d(1)(2)(1)(2)(0))

scala> res64: Option[play.api.libs.json.JsPath] = None

scala> res65: Option[play.api.libs.json.JsPath] = Some(/key)

使用 Play JSON 查询并查找 JSON 元素值的路径

Query and find the path of an JSON element value with Play JSON

scala

jsonpath

playframework