[英]How to use Joda DateTime with Play Json
I'm developing a Play application, and I'm trying to use a Joda DateTime object into my case class. 我正在开发一个Play应用程序,我正在尝试将Joda DateTime对象用于我的case类。
package model
import org.joda.time.DateTime
import play.api.libs.json._
case class User(name: String, created: DateTime)
object User {
implicit val yourJodaDateReads = Reads.jodaDateReads("yyyy-MM-dd'T'HH:mm:ss.SSSZ")
implicit val yourJodaDateWrites = Writes.jodaDateWrites("yyyy-MM-dd'T'HH:mm:ss.SSSZ'")
implicit val userFormat = Json.format[User]
def main(args: Array[String]) {
val value = Json.parse("{ \"name\" : \"hello\" , \"created\" : \"2015-07-16T20:32:04.046+02:00\" }")
println(Json.toJson(new User("user", new DateTime())))
println(Json.fromJson(value))
}
}
Based on this solution , I'm getting this error: 基于此解决方案 ,我收到此错误:
Error:(18, -1) Play 2 Compiler:
/activator-1.3.2/notifier-app/app/model/Test.scala:18: ambiguous implicit values:
both value yourJodaDateReads in object User of type => play.api.libs.json.Reads[org.joda.time.DateTime]
and value userFormat in object User of type => play.api.libs.json.OFormat[model.User]
I'm using Activator 1.3.2 and Play 2.3.8. 我正在使用Activator 1.3.2和Play 2.3.8。
Could you please advice me ? 你能告诉我一下吗?
Thanks in advance. 提前致谢。
update 更新
I understand there is a conflict with the implicit value in play.api.libs.json.Reads 我知道play.api.libs.json.Reads中的隐含值存在冲突
implicit val DefaultJodaDateReads = jodaDateReads("yyyy-MM-dd")
How can I resolve this issue ? 我该如何解决这个问题?
Expecting a better alternative, here my workaround: 期待更好的选择,在这里我的解决方法:
val dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSSZ"
val jodaDateReads = Reads[DateTime](js =>
js.validate[String].map[DateTime](dtString =>
DateTime.parse(dtString, DateTimeFormat.forPattern(dateFormat))
)
)
val jodaDateWrites: Writes[DateTime] = new Writes[DateTime] {
def writes(d: DateTime): JsValue = JsString(d.toString())
}
val userReads: Reads[User] = (
(JsPath \ "name").read[String] and
(JsPath \ "created").read[DateTime](jodaDateReads)
)(User.apply _)
val userWrites: Writes[User] = (
(JsPath \ "name").write[String] and
(JsPath \ "created").write[DateTime](jodaDateWrites)
)(unlift(User.unapply))
implicit val userFormat: Format[User] = Format(userReads, userWrites)
In play 2.6, the canonical way to serialize/deserialize joda DateTime json is by using the play-json-joda library. 在游戏2.6中,使用play-json-joda库序列化/反序列化joda DateTime json的规范方法。 Import the library by updating your build.sbt
. 通过更新build.sbt
导入库 。 Then create json reader and json writers like this : 然后像这样创建json reader和json writer:
import play.api.libs.json.JodaWrites
implicit val dateTimeWriter: Writes[DateTime] = JodaWrites.jodaDateWrites("dd/MM/yyyy HH:mm:ss")
import play.api.libs.json.JodaReads
implicit val dateTimeJsReader = JodaReads.jodaDateReads("yyyyMMddHHmmss")
I know this question has been answered for a while, but I found a more concise answer 我知道这个问题已经回答了一段时间,但我找到了一个更简洁的答案
val pattern = "yyyy-MM-dd'T'HH:mm:ss.SSSZ"
implicit val dateFormat = Format[DateTime](Reads.jodaDateReads(pattern), Writes.jodaDateWrites(pattern))
implicit val userFormat = Json.format[User]
Try these: 试试这些:
implicit val dateWrites = jodaDateWrites("yyyy-MM-dd'T'HH:mm:ss.SSSZ")
implicit val dateReads = jodaDateReads("yyyy-MM-dd'T'HH:mm:ss.SSSZ")
https://github.com/playframework/playframework/blob/master/framework/src/play-json/src/main/scala/play/api/libs/json/Writes.scala#L411 https://github.com/playframework/playframework/blob/master/framework/src/play-json/src/main/scala/play/api/libs/json/Writes.scala#L411
https://github.com/playframework/playframework/blob/master/framework/src/play-json/src/main/scala/play/api/libs/json/Reads.scala#L645 https://github.com/playframework/playframework/blob/master/framework/src/play-json/src/main/scala/play/api/libs/json/Reads.scala#L645
I think you should set the User
type in Json.toJson
and Json.fromJson
functions. 我认为你应该在Json.toJson
和Json.fromJson
函数中设置User
类型。 Instead of 代替
println(Json.toJson(new User("user", new DateTime())))
println(Json.fromJson(value))
try: 尝试:
println(Json.toJson[User](new User("user", new DateTime())))
println(Json.fromJson[User](value))
When you set the type explicitly framework will know what reads/writes to use. 当您明确设置类型时,框架将知道要使用的读/写内容。
Update: It is not necessarily to set type for Json.toJson
function because you pass User
object as function argument and framework determines the type in runtime. 更新:不一定要为Json.toJson
函数设置类型,因为您将User
对象作为函数参数传递,框架确定运行时的类型。 But for Json.fromJson[User]
you must set the type, otherwise framework doesn't know type of the object you want to read. 但对于Json.fromJson[User]
您必须设置类型,否则框架不知道您要读取的对象的类型。
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