如何解析json與使用蛇情況（下劃線符號），而不是駱駝案例噴霧json

Question

如何解析json噴霧json使用蛇案（下劃線符號），而不是駱駝案？

E.g.

case class Test(subjectDescription: String) 
"{\"subject_description\":\"Medicine\"}".parseJson.convertTo[Test] 

應該工作，而不是拋出異常。

Answer 1

此答案取自https://groups.google.com/forum/#!msg/spray-user/KsPIqWDK0AY/HcanflgRzMcJ。把它放在SO上，因爲SEO更好。

/** 
* A custom version of the Spray DefaultJsonProtocol with a modified field naming strategy 
*/ 
trait SnakifiedSprayJsonSupport extends DefaultJsonProtocol { 
    import reflect._ 

    /** 
    * This is the most important piece of code in this object! 
    * It overrides the default naming scheme used by spray-json and replaces it with a scheme that turns camelcased 
    * names into snakified names (i.e. using underscores as word separators). 
    */ 
    override protected def extractFieldNames(classTag: ClassTag[_]) = { 
    import java.util.Locale 

    def snakify(name: String) = PASS2.replaceAllIn(PASS1.replaceAllIn(name, REPLACEMENT), REPLACEMENT).toLowerCase(Locale.US) 

    super.extractFieldNames(classTag).map { snakify(_) } 
    } 

    private val PASS1 = """([A-Z]+)([A-Z][a-z])""".r 
    private val PASS2 = """([a-z\d])([A-Z])""".r 
    private val REPLACEMENT = "$1_$2" 
} 

object SnakifiedSprayJsonSupport extends SnakifiedSprayJsonSupport 

import SnakifiedSprayJsonSupport._ 

object MyJsonProtocol extends SnakifiedSprayJsonSupport { 
    implicit val testFormat = jsonFormat1(Test.apply) 
} 

Answer 2

像這樣：

case class Test(subjectDescription: String) 
implicit val testFormat = jsonFormat(Test.apply, "subject_description") 
"{\"subject_description\":\"Medicine\"}".parseJson.convertTo[Test] 

這裏的技巧是jsonFormat函數使用字符串參數爲JSON對象鍵。