斯卡拉json4s我如何通過條件

Question

我有JSON（例如）提取領域：

{ 
    "name": "", 
    "count": 2, 
    "children": { 
    "app_open": { 
     "name": "app_open", 
     "count": 1, 
     "children": { 
     "session_end": { 
      "name": "session_end", 
      "count": 1, 
      "children": {} 
     } 
     } 
    }, 
    "app_install": { 
     "name": "app_install", 
     "count": 2, 
     "children": { 
     "session_end": { 
      "name": "session_end", 
      "count": 2, 
      "children": {} 
     } 
     } 
    }, 
    "app_instal1l": { 
     "name": "app_instal1l", 
     "count": 3, 
     "children": { 
     "app_open": { 
      "name": "app_open", 
      "count": 3, 
      "children": { 
      "session_end": { 
       "name": "session_end", 
       "count": 3, 
       "children": {} 
      } 
      } 
     } 
     } 
    } 
    } 
} 

我需要提取所有的計數，其中「名」 =「app_open」。

我試圖做到這一點與json4s庫：

val name = jsonInput filterField { 
      case JField("name", "app_open") => true 
      case _ => false 
     } 
println("name = " + URL) 

我和輸出建議我得帶徒「app_open」的東西，但我得到：

name = List((name,JString(app_open)), (name,JString(session_end)), 
(name,JString(app_open)), (name,JString(session_end))) 

我」什麼在這裏做錯了嗎？ 謝謝！

Answer 1

編譯器錯誤是相當清楚的：

Error: type mismatch; 
found : String("app_open") 
required: org.json4s.JsonAST.JValue 
    case JField("name", "app_open") => true 
        ^

這是因爲type JField = (String, JValue)。使用JValue代替String這樣的：

val name = jsonInput filterField { 
    case JField("name", JString("app_open")) => true 
    case _ => false 
}