据我所知,实现这一点的简单方法并不存在,但是,为每个对象创建一个“默认”阅读器应该不难做到,例如:
case class VehicleColorForAdd(
name: String,
rgb: String
)
object VehicleColorForAdd {
implicit val jsonFormat: Format[VehicleColorForAdd] = Json.formats[VehicleColorForAdd]
}
这样您就可以通过简单地使用对象来访问隐式,因此您可以拥有包含该对象的其他对象而没有问题:
case class BiggerModel(
vehicleColorForAdd: VehicleColorForAdd
)
object BiggerModel{
implicit val jsonFormat: Format[BiggerModel] = Json.format[BiggerModel]
}
遗憾的是,您需要为每种类类型执行此操作,但您可以使用自己的“扩展”播放转换器,例如,这是我的一些默认阅读器:
package common.json
import core.order.Order
import org.joda.time.{ DateTime, LocalDateTime }
import org.joda.time.format.DateTimeFormat
import core.promotion.{ DailySchedule, Period }
import play.api.libs.functional.syntax._
import play.api.libs.json.Reads._
import play.api.libs.json._
import play.api.libs.json.{ JsError, JsPath, JsSuccess, Reads }
import scala.language.implicitConversions
/**
* General JSon readers and transformations.
*/
object JsonReaders {
val dateTimeFormat = "yyyy-MM-dd HH:mm:ss"
class JsPathHelper(val path: JsPath) {
def readTrimmedString(implicit r: Reads[String]): Reads[String] = Reads.at[String](path)(r).map(_.trim)
def readUpperString(implicit r: Reads[String]): Reads[String] = Reads.at[String](path)(r).map(_.toUpperCase)
def readNullableTrimmedString(implicit r: Reads[String]): Reads[Option[String]] = Reads.nullable[String](path)(r).map(_.map(_.trim))
}
implicit val localDateTimeReader: Reads[LocalDateTime] = Reads[LocalDateTime]((js: JsValue) =>
js.validate[String].map[LocalDateTime](dtString =>
LocalDateTime.parse(dtString, DateTimeFormat.forPattern(dateTimeFormat))))
val localDateTimeWriter: Writes[LocalDateTime] = new Writes[LocalDateTime] {
def writes(d: LocalDateTime): JsValue = JsString(d.toString(dateTimeFormat))
}
implicit val localDateTimeFormat: Format[LocalDateTime] = Format(localDateTimeReader, localDateTimeWriter)
implicit val dateTimeReader: Reads[DateTime] = Reads[DateTime]((js: JsValue) =>
js.validate[String].map[DateTime](dtString =>
DateTime.parse(dtString, DateTimeFormat.forPattern(dateTimeFormat))))
implicit def toJsPathHelper(path: JsPath): JsPathHelper = new JsPathHelper(path)
val defaultStringMax: Reads[String] = maxLength[String](255)
val defaultStringMinMax: Reads[String] = minLength[String](1) andKeep defaultStringMax
val rgbRegex: Reads[String] = pattern("""^#([\da-fA-F]{2})([\da-fA-F]{2})([\da-fA-F]{2})$""".r, "error.invalidRGBPattern")
val plateRegex: Reads[String] = pattern("""^[\d\a-zA-Z]*$""".r, "error.invalidPlatePattern")
val minOnlyWordsRegex: Reads[String] = minLength[String](2) keepAnd onlyWordsRegex
val positiveInt: Reads[Int] = min[Int](1)
val zeroPositiveInt: Reads[Int] = min[Int](0)
val zeroPositiveBigDecimal: Reads[BigDecimal] = min[BigDecimal](0)
val positiveBigDecimal: Reads[BigDecimal] = min[BigDecimal](1)
def validLocalDatePeriod()(implicit reads: Reads[Period]) =
Reads[Period](js => reads.reads(js).flatMap { o =>
if (o.startPeriod isAfter o.endPeriod)
JsError("error.startPeriodAfterEndPeriod")
else
JsSuccess(o)
})
def validLocalTimePeriod()(implicit reads: Reads[DailySchedule]) =
Reads[DailySchedule](js => reads.reads(js).flatMap { o =>
if (o.dailyStart isAfter o.dailyEnd)
JsError("error.dailyStartAfterDailyEnd")
else
JsSuccess(o)
})
}
然后,您只需要导入此对象即可访问所有这些隐式转换器:
package common.forms
import common.json.JsonReaders._
import play.api.libs.json._
/**
* Form to add a model with only one string field.
*/
object SimpleCatalogAdd {
case class Data(
name: String
)
implicit val dataReads: Reads[Data] = (__ \ "name").readTrimmedString(defaultStringMinMax).map(Data.apply)
}