Question

我有以下类需要序列化反序列化器

 case class User(userId: Int, userName: String, email: String,        
 password: String) {

 def this() = this(0, "", "", "")

def this(userId: Int){
this(userId, "", "", "" )
}

def this(userId: Int, userName: String){
  this(userId, userName, "", "" )
}

def this(userId: Int, userName: String, email: String){
  this(userId, userName,email, "" )
}

def this(password: String){
  this(0, "","", password )
 }
}

我有多个构造函数的用户案例类。这样可以将用户创建为

var u =新用户（mid，mname，memail，mpassword）
var u =新用户（mid，mname）

我期待JSON请求为

JSON请求类型1： -

 "teamMembers" : [ {
    "userId" : 1,
    "userName" : "user name",
    "email" : "eamil",
    "password" : "password"
  }, {
    "userId" : 2,
    "userName" : "user name 2",
    "email" : "email2",
    "password" : "pssword"
  } ]

OR JSON请求类型1： -

"teamMembers" : [ {
    "userId" : 1,
    "userName" : "user name"
  }, {
    "userId" : 2,
    "userName" : "user name 2"
  } ]

我实现了JSON序列化器反序列化器，它仅对第一类请求

  trait UserJson extends Controller {
  implicit val userWrites: Writes[User] = (
      (__ \ "userId").write[Int] ~
      (__ \ "userName").write[String] ~
      (__ \ "email").write[String] ~
      (__ \ "password").write[String]
    )(unlift(User.unapply))

   implicit val userReads: Reads[User] = (
      (__ \ "userId").read[Int](min(0) keepAnd max(150)) ~
      (__ \ "userName").read[String](minLength[String](2)) ~
      (__ \ "email").read[String](minLength[String](2)) ~
      (__ \ "password").read[String](minLength[String](2))
    )(User.apply _)
}

但是对于类型2，JSON请求不起作用。你能告诉我如何申请2型JSON请求吗？提前谢谢！

Answer 1

您可以将Json读取/写入用作隐式值

例如：

Json.toJson(user)(userWrites1)
Json.toJson(user)(userWrites2)

Answer 2

听起来像email而password是Optional。您可以将email和password设置为Option并使用writeNullable，如下所示。那是你在找什么？

旁注：您的this def看起来很奇怪，在Scala中，您通常会使用apply来实现这一目标。

case class User(userId: Int, userName: String, email: Option[String],  password: Option[String])

implicit val userWrites: Writes[User] = (
  (__ \ "userId").write[Int] ~
  (__ \ "userName").write[String] ~
  (__ \ "email").writeNullable[String] ~
  (__ \ "password").writeNullable[String]
)(unlift(User.unapply))

如何编写Scala Play框架自定义类的多个JSON序列化器解串器？

2 个答案: