Scala初学者在多个文件上编译和运行scala程序

Question

这是代码。

mongoclient.scala

package com.scalainaction.mongo
import com.mongodb._

class MongoClient(val host:String, val port:Int) {
    require(host != null, "You have to provide a host name")
    val underlying = new com.scalainaction.mongo.Mongo
    def this() = this("127.0.0.1", 27017)
    def version = underlying.getVersion
    def dropDB(name:String) = underlying.dropDatabase(name) 
    def createDB(name:String) = DB(underlying.getDB(name)) 
    def db(name:String) = DB(underlying.getDB(name))
}

数据库。斯卡拉

package com.scalainaction.mongo
import com.mongodb.{DB => MongoDB}
import scala.collection.convert.Wrappers._

class DB private(val underlying: MongoDB) {
    private def collection(name: String) = underlying.getCollection(name)
    def readOnlyCollection(name: String) = new DBCollection(collection(name)) 

    def administrableCollection(name: String) = new
        DBCollection(collection(name)) with Administrable

    def updatableCollection(name: String) = new
        DBCollection(collection(name)) with Updatable

    def collectionNames = for(name 

DBCollection。斯卡拉

package com.scalainaction.mongo
import com.mongodb.{DBCollection => MongoDBCollection } 
import com.mongodb.DBObject

class DBCollection(override val underlying: MongoDBCollection) extends ReadOnly

trait ReadOnly {
  val underlying: MongoDBCollection
  def name = underlying.getName
  def fullName = underlying.getFullName
  def find(doc: DBObject) = underlying.find(doc)
  def findOne(doc: DBObject) = underlying.findOne(doc)
  def findOne = underlying.findOne
  def getCount(doc: DBObject) = underlying.getCount(doc)
}

trait Administrable extends ReadOnly {
  def drop: Unit = underlying.drop
  def dropIndexes: Unit = underlying.dropIndexes
}

trait Updatable extends ReadOnly {
  def -=(doc: DBObject): Unit = underlying.remove(doc)
  def +=(doc: DBObject): Unit = underlying.save(doc)
}

所有程序都放在同一个包com.scalainaction.mongo内。

我不使用IDE，所以我通过运行来编译这些文件

scalac mongoclient.scala DB.scala DBCollection.scala

我的$CLASSPATH包括mongodb。jar文件，并指向com。缩放操作。我的应用程序目录中的mongo文件夹

现在，我打算通过运行scala quickTour来运行一个使用该包的程序。scala-cp$CLASSPATH `

import com.scalainaction.mongo._
import com.mongodb.BasicDBObject

def client = new MongoClient("127.0.0.1", 27017)
def db = client.db("mydb")

for(name 

但是我的应用程序找不到MongoClient类，我得到了这个错误

quickTour.scala:1: error: object scalainaction is not a member of package com
import com.scalainaction.mongo._
           ^
/Users/sid/scala_apps/quickTour.scala:4: error: MongoClient does not have a constructor
def client = new MongoClient("127.0.0.1", 27017)
             ^
two errors found

我不明白为什么它找不到构造函数。我用def this方法定义了一个重载的构造函数

为什么它找不到com.scalanation.mongo?

如果你能帮上忙我会很感激的

**更新**

我的com/scalainaction/mongo文件夹中的文件是

Administrable$class.class       DB$.class               ReadOnly$class.class
Administrable.class         DB.class                ReadOnly.class
DB$$anon$1.class            DBCollection.class          Updatable$class.class
DB$$anon$2.class            MongoClient$$anonfun$1.class        Updatable.class
DB$$anonfun$collectionNames$1.class MongoClient.class

Answer 1

问题是您的com和/或com/scalainaction文件夹为空。在那里开设一些课程，应该会奏效。