有什么方法可以将嵌套的JSON值映射到字段而不需要额外的类?我有一个JSON响应
{
"title": "Warriors",
"artist": "Imagine Dragons",
"apple_music": {
"url": "https://music.apple.com/us/album/warriors/1440831203?app=music&at=1000l33QU&i=1440831624&mt=1",
"discNumber": 1,
"genreNames": [
"Alternative",
"Music"
],
}
}
但从 apple_music
我只需要 url
值。所以我决定创建Kotlin数据类,并尝试了用 @Json
注释
data class Song(
val title: String,
val artist: String,
@Json(name = "apple_music.url")
val appleMusicUrl: String
)
然而,这并不奏效。它在运行时抛出一个异常
Required value 'appleMusicUrl' (JSON name 'apple_music.url') missing at $
下面的代码可以使用
data class Song(
val title: String,
val artist: String,
@Json(name = "apple_music")
val appleMusic: AppleMusic
)
data class AppleMusic(val url: String)
我有几个嵌套的值,为它们创建额外的类是相当夸张的。有没有比创建嵌套类更好的方法呢?apple_music
节点?
你可以通过以下方式来实现这一点 使用@JsonQualifier的交替类型适配器。. 例如:
@Retention(RUNTIME)
@JsonQualifier
annotation class AppleMusicUrl
data class Song(
val title: String,
val artist: String,
@AppleMusicUrl
val appleMusicUrl: String
)
@FromJson
@AppleMusicUrl
fun fromJson(json: Map<String, Any?>): String {
return json.getValue("url") as String
}