I am new scala and SBT. I am trying write a pursuing engine which can read the JSON string to object and write back Object to JSON string. To do that I am using eclipse as IDE and SBT(0.13.13) as build tool and jackson. I am getting some error while trying to import the dependency in scala file. My steps as follows:
I have added this two dependency in build.sbt of my project
libraryDependencies += "com.fasterxml.jackson.core" % "jackson-databind" % "2.5.3"
libraryDependencies += "com.fasterxml.jackson.module" % "jackson-module-scala_2.11" % "2.8.8"
Compile the project from SBT console with "compile" command
Creating a scala object for DAO object, which will contain the data and transfer as JSON
But when I am trying to import this in scala source file:
import com.fasterxml.jackson.databind.{DeserializationFeature, ObjectMapper}
import com.fasterxml.jackson.module.scala.experimental.ScalaObjectMapper
import com.fasterxml.jackson.module.scala.DefaultScalaModule
It's giving some compilation error:
object fasterxml is not a member of package com
But my compilation, which I did to download those dependency, ends up with success and showing download as [SUCCESSFUL]
I think I am missing something, can any one help me out in this regard?
As part of experiment I have added MySql dependency in my project as:
libraryDependencies += "mysql" % "mysql-connector-java" % "5.1.40"
Which is working properly, I am able to connect the MySql Server from scala code.
One more thing as in Maven we can update or if we save the POM file, maven downloads all those dependency automatically. Is that the same in SBT or every time after adding dependency in build.sbt I have to "reload" and "compile" to download?
Here are some of the steps you need to follow
1) clean your project in eclipse (eclipse might cache dependencies)
2) make sure your project directories are as explained in here
3) If above two steps doesn't work do
import _root_.com.fasterxml.jackson.databind.{DeserializationFeature, ObjectMapper}
import _root_.com.fasterxml.jackson.module.scala.experimental.ScalaObjectMapper
import _root_.com.fasterxml.jackson.module.scala.DefaultScalaModule
Hope you get it solved
Related
I'm having trouble using joda-time in my scala project in scala-ide. I have the following line:
import org.joda.time.DateTime
But it causes the following error: object joda is not a member of package org
That's what I did:
I put these lines in build.sbt:
libraryDependencies += "joda-time" % "joda-time" % "2.9.3"
libraryDependencies += "org.joda" % "joda-convert" % "1.8"
Then I ran reload in my sbt session.
Then I ran update in my sbt session.
So what did I miss?
sbt eclipse fixed the thing.
But it was another issue: scala-ide ceased to find main class when trying to run any module extended from App. Removing src folder and creating it again nailed that bitch down.
try to delete all joda-time jars from your computer, and reload the project again,
it seems that the jar is corrupted.
I am doing my first Lift project and want to add a database. Following a book, I added the following dependency to build.sbt:
"net.liftweb" %% "lift-mapper" % liftVersion % "compile",
And then, in Boot.scala, the import
import net.liftweb.mapper._
Now the project doesn't compile, with Boot.scala giving the error
object mapper is not a member of package net.liftweb
But other sources around the Internet seem to suggest that my imports are OK.
Where does the dependency problem come from?
It turned out that this is a problem of Eclipse, which cannot setup the dependencies correctly.
I had to close the project in Eclipse and delete the hidden files .classpath and .project. Then get into SBT and run
eclipse
(the project has to use the sbteclipse plugin as described in the Lift cookbook). This recreates the project files with the correct dependencies.
Afterwards, Eclipse compiled the code as expected. It seems this will be needed every time a change is made to build.sbt.
I'm trying to make my first tests with Scala and with Play framework.
I have installed play 2.2.0, which seems to be the last version, with the standalone package. After that, I've been able to create a new application, compile and run it.
I've tried to start to use Anorm package to access to the database, but I've found a blocking error which I can't find on the docs. I don't know if that means that is so obvious, but after adding:
package controllers
import play.api._
import play.api.mvc._
import play.db.anorm._ //(this is the new line)
object Application extends Controller {
def index = Action {
Ok(views.html.index("Your new application is ready."))
}
}
It fails with:
object db is not a member of package play
I've seen this:
https://groups.google.com/forum/#!msg/play-framework/RUbmEVsw2rY/UOE5mNs1WjoJ
Where they talk about adding the dependency to jdbc, which seems to be already in my build.sbt.
libraryDependencies ++= Seq(
jdbc,
anorm,
cache
)
I've also found this thread here:
play.db package not found in play 2.1.3
But I can't find a build.scala file on my project. Not using any IDE by now, just play console (run & compile commands).
Thanks a lot!
In fact (as the error explains), there is no package play.db.anorm._ in version 2.2.0. Try use import anorm._ instead.
You need the following libraries
slick
play-jdbc
anorm
This is how my dependencies look like in build.sbt :
libraryDependencies ++= Seq(
"com.typesafe.slick" % "slick_2.10" % "2.1.0",
"org.postgresql" % "postgresql" % "9.4-1201-jdbc41",
"com.typesafe.play" % "play-jdbc_2.10" % "2.4.0-RC1",
cache,
anorm
)
Search for the latest version of library at Maven Central Repository
Even after reading: Scala, problem with a jar file, I'm still a bit confused. I am trying to import some packages into my Scala file, and the interpreter is not recognizing them even after adding to classpath.
One example:
I have the import statement:
import org.json4s._
I downloaded the .jar from here: http://mvnrepository.com/artifact/org.json4s/json4s-native_2.10/3.2.4
and added to the interpreter classpath using:
scala> :cp /Users/aspangher13/Downloads/json4s-native_2.10-3.2.4.jar
Scala acknowledges the classpath:
Your new classpath is: ".:/Users/aspangher13/Downloads/json4s-native_2.10-3.2.4.jar:/Users/aspangher13/Downloads/jna-3.5.2.jar"
But still throws this error:
<console>:7: error: object scalatra is not a member of package org
import org.json4s._
Can anyone see what I'm doing wrong? Thanks!!
And as a followup, does anyone know where to find the package: JsonAST._?
Go the simple and create a little sbt project.
First step - create a project
For your purposes you don't need a complex build. So just create two files:
./build.sbt
name := "name your project"
version := "0.1"
scalaVersion := "2.10.2" // or whatever you prefer
./project/build.properties
sbt.version=0.12.4
The just go to the project root folder and call sbt
Second step - add dependencies
Open your ./build.sbt file and add:
libraryDependency ++= Seq(
"org.scalatra" %% "scalatra" % "2.2.1",
"org.scalatra" %% "scalatra-scalate" % "2.2.1",
"org.scalatra" %% "scalatra-specs2" % "2.2.1" % "test",
"org.json4s" %% "json4s-native % "3.2.4",
"net.java.dev.jna" & "jna" & "3.5.2"
)
Step three - run the console
Don't forget to reload sbt with reload task, and then call console or console-quick task. This should work.
But there are easier ways to do this:
1) Use gitter8 - Scalatra gitter8 project
2) Read little into about Scalatra sbt dependencies
Still not sure how :cp works but if you execute
scala -classpath "list of jars colon separated"
then inside the REPL do your imports it should work
import org.json4s._
import org.xyz
However, when you try to use the classes you are likely to be missing transitive dependencies required by json4s and so we come back to the sbt example # 4lex1v describes, which will handle this. Creating a little project and running sbt console will indeed greatly simplify this.
Seems like the -classpath and :cp are primarily meant to make your code available in the shell and then only if you understand all of the transitive dependencies, or have none.
I want to use http://dispatch.databinder.net/Dispatch.html .
The site indicates I must add this to project/plugins.sbt:
libraryDependencies += "net.databinder.dispatch" %% "core" % "0.9.1"
which I did. I then restarted the play console and compiled.
Importing doesnt work:
import dispatch._
Guess I have been silly, but then I never used a build system when using Java.
How must I trigger the process that downloads/builds the package? Where are the jars (or equivalent) stored; can I reuse them? When is the package available for use by the Play application?
It doesn't say you should add it to project/plugins.sbt. That is the wrong place. It says to add to the build.sbt file, on the root of your project. Being a Play project, project/Build.scala might be more appropriate -- I don't know if it will pick up settings from build.sbt or not.
To add the dependency in your Build.scala:
val appDependencies = Seq(
"net.databinder.dispatch" %% "core" % "0.9.1"
)
You probably need to run sbt update.
From the sbt Command Line Reference:
update Resolves and retrieves external dependencies as described in library dependencies.