3
我需要將這個JSON遊戲框架:類型不匹配JsValue/JsValueWrapper
{ "matchItem": { "collection": { "fieldName": [ "value1", "value2" ] } } }
轉換爲該MongoDB的投影:
{ "collection": { "$elemMatch": { "fieldName": "value1", "fieldName": "value2" } }
這下面是我的代碼:
def toProjection(json: JsValue) = {
json.getOpt(__ \ "matchItem").map { value =>
val obj = value.as[JsObject]
for (key <- obj.keys) { obj.getOpt(__ \ key).map { matchObj =>
for (matchKey <- matchObj.as[JsObject].keys) { matchObj.getOpt(__ \ matchKey).map { items =>
val fields = items.as[Seq[JsValue]].map(item => (matchKey -> item))
seq += key -> Json.obj("$elemMatch" -> Json.obj(fields))
}}
}}
}
if (seq.length > 0) JsObject(seq) else json
}
val json = """{ "matchItem": { "collection": { "fieldName": [ "value1", "value2" ] } } }"""
val proj = toProjection(json)
這代碼不編譯,我總是得到以下錯誤信息:
[error] /home/j3d/Projects/test/app/services/Test.scala:82: type mismatch;
[error] found : Seq[(String, play.api.libs.json.JsValue)]
[error] required: (String, play.api.libs.json.Json.JsValueWrapper)
[error] seq += fieldMaps.fromPublic(key) -> Json.obj("$elemMatch" -> Json.obj(fields))
[error] ^
我有點失落。我知道Json.obj
是一個輔助的方法來建立JsObject
實例:
JsObject(Seq(
"key1" -> JsString("value1"),
"key2" -> JsString("value2")
...
))
...相當於:
Json.obj("key1" -> "value1", "key2" -> "value2")
在上面我的代碼,該fields
值是Seq[(String, play.api.libs.json.JsValue)]
...所以我不不明白爲什麼它不起作用。任何幫助將非常感激。
我看到有一些關於JsValue和JsValueWrapper的討論[這裏](https://groups.google.com/forum/#!topic/play-framework/Bs5pEy2nAzs)可能會有所幫助。 – wwkudu