使用Play 2.0.1我定义了以下路由：
GET /demo/list controllers.Demos.listDemos(page: Int ?= 0,orderBy: Int ?= 1,nameFilter: String ?= "",versionFilter: Long ?= -1,tagFilter: List[String] ?= Nil)
但我在编译时遇到这个错误：
No QueryString binder found for type List[String]. Try to implement an implicit QueryStringBindable for this type.
我发现Play 2.1-RC(尚未正式发布)的代码可以解决这个问题：
/**
* QueryString binder for List
*/
implicit def bindableList[T: QueryStringBindable] = new QueryStringBindable[List[T]] {
def bind(key: String,params: Map[String,Seq[String]]) = Some(Right(bindList[T](key,params)))
def unbind(key: String,values: List[T]) = unbindList(key,values)
}
/**
* QueryString binder for java.util.List
*/
implicit def bindableJavaList[T: QueryStringBindable] = new QueryStringBindable[java.util.List[T]] {
def bind(key: String,params).asJava))
def unbind(key: String,values: java.util.List[T]) = unbindList(key,values.asScala)
}
private def bindList[T: QueryStringBindable](key: String,Seq[String]]): List[T] = {
for {
values <- params.get(key).toList
rawValue <- values
bound <- implicitly[QueryStringBindable[T]].bind(key,Map(key -> Seq(rawValue)))
value <- bound.right.toOption
} yield value
}
private def unbindList[T: QueryStringBindable](key: String,values: Iterable[T]): String = {
(for (value <- values) yield {
implicitly[QueryStringBindable[T]].unbind(key,value)
}).mkString("&")
}
但经过几个小时的尝试,Play仍然没有找到代码.我已经尝试使用自定义对象和隐式转换到该对象,但它仍然无法正常工作.
如何强制Play进行隐式转换？
更新
如果可能的话我想避免使用2.1-SNAPSHOT,因为我担心它的稳定性,但如果没有别的办法,我会使用它.我尝试了4e6的解决方案,但它不起作用：
[warn] :::::::::::::::::::::::::::::::::::::::::::::: [warn] :: UNRESOLVED DEPENDENCIES :: [warn] :::::::::::::::::::::::::::::::::::::::::::::: [warn] :: org.slf4j#slf4j-api;1.6.1: configuration not found in org.slf4j#slf4j-api;1.6.1: 'compile'. It was required from org.hibernate#hibernate-validator;4.2.0.Final compile [warn] :: commons-codec#commons-codec;1.4: configuration not found in commons-codec#commons-codec;1.4: 'compile'. It was required from org.apache.httpcomponents#httpclient;4.1.2 compile [warn] ::::::::::::::::::::::::::::::::::::::::::::::
我的sbt插件包含这个：
// Comment to get more information during initialization logLevel := Level.Warn // The Typesafe repository resolvers ++= Seq( Resolver.url("Typesafe Ivy Snapshots",url("http://repo.typesafe.com/typesafe/ivy-snapshots/"))(Resolver.ivyStylePatterns),"Typesafe Releases" at "http://repo.typesafe.com/typesafe/releases/","Typesafe Snapshots" at "http://repo.typesafe.com/typesafe/snapshots/","DefaultMavenRepository" at "http://repo1.maven.org/maven2/","JavaNet1Repository" at "http://download.java.net/maven/1/") // Use the Play sbt plugin for Play projects addSbtPlugin("play" % "sbt-plugin" % "2.1-SNAPSHOT")
解决方法
我终于解决了.使用的代码是：
在模型下,文件QueryBinders.scala：
package models
import play.api.mvc.{JavascriptLitteral,QueryStringBindable}
/**
* Created with IntelliJ IDEA.
* User: pvillega
* Date: 07/05/12
* Time: 12:06
* QueryStringBinders for some data types missing in 2.0.1
*/
//Todo: remove when updating to 2.1
object QueryBinders {
/**
* QueryString binder for List
*/
implicit def bindableList[T: QueryStringBindable] = new QueryStringBindable[List[T]] {
def bind(key: String,values)
}
private def bindList[T: QueryStringBindable](key: String,value)
}).mkString("&")
}
/**
* Convert a Scala List[T] to Javascript array
*/
implicit def litteralOption[T](implicit jsl: JavascriptLitteral[T]) = new JavascriptLitteral[List[T]] {
def to(value: List[T]) = "[" + value.map { v => jsl.to(v)+"," } +"]"
}
}
在Build.scala上：
val main = PlayProject(appName,appVersion,appDependencies,mainLang = SCALA).settings(
// Add your own project settings here
lessEntryPoints <<= baseDirectory(_ / "app" / "assets" / "stylesheets" ** "style.less"),routesImport += "models.QueryBinders"
)
更新到2.1时必须删除它,但它可以工作,它避免了我尝试将项目更新为2.1快照的所有问题.
