Question

我将在play 2.3中使用正则表达式和Forms开发自定义验证根据我开发的官方文档：

  case class AlphaNumeric(str: String)

  val anForm = Form(
    mapping(
      "str" -> alphaNumCheck
    )(AlphaNumeric.apply)(AlphaNumeric.unapply)
  )

  val numberConstraint = """\d+""".r
  val alphaNumConstraint: Constraint[String] = Constraint("constraints.password")({
    plainText =>
      val errors = numberConstraint.findFirstIn(plainText) match {
        case None => Nil
        case Some(_) => Seq(ValidationError("Need to contain at least one number"))
      }
      if (errors.isEmpty) {
        Valid
      } else {
        Invalid(errors)
      }
  })

  val alphaNumCheck: Mapping[String] = nonEmptyText.verifying(alphaNumConstraint)

  def alphaNumAction() = Action {
    implicit request => {

      anForm.bindFromRequest fold (
        formWithErrors => {
          BadRequest(anForm.errorsAsJson)
        },
        newAccountInfo => {
          Ok(Json.obj("message" -> "success"))
        }
      )
    }
  }

但是当我调用此操作时，我收到500内部服务器错误。

Internal server error, for (POST) [/alpha] ->

java.lang.ExceptionInInitializerError: null
    at Routes$$anonfun$routes$1$$anonfun$applyOrElse$3$$anonfun$apply$3.apply(routes_routing.scala:137) ~[na:na]
    at Routes$$anonfun$routes$1$$anonfun$applyOrElse$3$$anonfun$apply$3.apply(routes_routing.scala:137) ~[na:na]
    at play.core.Router$HandlerInvokerFactory$$anon$13$$anon$14.call(Router.scala:217) ~[play_2.11-2.3.2.jar:2.3.2]
    at play.core.Router$Routes$TaggingInvoker.call(Router.scala:464) ~[play_2.11-2.3.2.jar:2.3.2]
    at Routes$$anonfun$routes$1$$anonfun$applyOrElse$3.apply(routes_routing.scala:137) ~[na:na]
Caused by: java.lang.NullPointerException: null
    at play.api.data.ObjectMapping5.<init>(ObjectMappings.scala:272) ~[play_2.11-2.3.2.jar:2.3.2]
    at play.api.data.Forms$.mapping(Forms.scala:77) ~[play_2.11-2.3.2.jar:2.3.2]
    at controllers.AccountController$.<init>(AccountController.scala:71) ~[na:na]
    at controllers.AccountController$.<clinit>(AccountController.scala) ~[na:na]
    at Routes$$anonfun$routes$1$$anonfun$applyOrElse$3$$anonfun$apply$3.apply(routes_routing.scala:137) ~[na:na]
[error] application - Error while rendering default error page

当我在某个标准上更改自定义alphaNumCheck时nonEmptyText一切正常。

问题是如何使用正则表达式进行正确的自定义验证？

由于

Answer 1

您收到NullPointerException - alphaNumCheck为空。移动

val alphaNumCheck: Mapping[String] = nonEmptyText.verifying(alphaNumConstraint)

到val anForm =

的顶部

见简单示例：

scala> :pa
// Entering paste mode (ctrl-D to finish)

class A {

val a = b

val b = "AAA"

}

// Exiting paste mode, now interpreting.

<console>:9: warning: Reference to uninitialized value b
       val a = b
               ^
defined class A

scala> val instance = new A
instance: A = A@4ac68d3e

scala> instance.a
res3: String = null

问题在于初始化顺序。在a之前创建了b - 在行val a = b中，b的值为null。

如果我添加lazy，一切都会好的。

scala> :pa
// Entering paste mode (ctrl-D to finish)

class A {

lazy val a = b

val b = "AA" 
}

// Exiting paste mode, now interpreting.

defined class A

scala> val instance = new A
instance: A = A@d7b1517

scala> instance.a
res4: String = AA

PlayFramework：表单正则表达式验证

1 个答案: