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问题:
I implemented a Scalatra servlet and now want to create an executable jar, just like described in this tutorial: http://www.scalatra.org/2.2/guides/deployment/standalone.html
I use IntelliJ IDEA with the Scala plugin for development and sbt to build and run my servlet (I used sbt-idea to generate the project files).
My problem is that the jetty packages that the JettyLauncher in the tutorial uses cannot be found when I try to compile my project.
UPDATE: Using Matt's answer I was able to compile and run the JettyLauncher. However, I still have problems with sbt-assembly (https://github.com/sbt/sbt-assembly). I followed the instruction in the readme, but I get the following error when trying to execute the assembly task:
[error] Not a valid command: assembly
[error] No such setting/task
[error] assembly
[error] ^
UPDATE 2: Thanks to Matt I now have a working build.scala and I can generate a executable jar using the assembly task. However, sbt-assembly does not add the content of /src/main/webapp to the jar.
I use this folder to store my HTML, CSS, and JavaScript files.
If Scalatra can't match a route, it serves these files, which works when running the servlet using container:start.
Additionally, I store some files that the server needs in /src/main/webapp/WEB-INF. These files are also not added to the jar.
My build.scala looks like this:
import sbt._
import Keys._
import org.scalatra.sbt._
import org.scalatra.sbt.PluginKeys._
import com.mojolly.scalate.ScalatePlugin._
import ScalateKeys._
import sbtassembly.Plugin._
import AssemblyKeys._
object SketchlinkBuild extends Build {
val Organization = "de.foobar"
val Name = "Foobar"
val Version = "0.1"
val ScalaVersion = "2.10.0"
val ScalatraVersion = "2.2.0"
lazy val project = Project (
"foobar",
file("."),
settings = Defaults.defaultSettings ++ ScalatraPlugin.scalatraWithJRebel ++ scalateSettings ++ assemblySettings ++ Seq(
organization := Organization,
name := Name,
version := Version,
scalaVersion := ScalaVersion,
resolvers += Classpaths.typesafeReleases,
libraryDependencies ++= Seq(
"org.scalatra" %% "scalatra" % ScalatraVersion,
"org.scalatra" %% "scalatra-scalate" % ScalatraVersion,
"org.scalatra" %% "scalatra-specs2" % ScalatraVersion % "test",
"ch.qos.logback" % "logback-classic" % "1.0.6" % "runtime",
"org.eclipse.jetty" % "jetty-webapp" % "8.1.8.v20121106" % "compile;container",
"org.eclipse.jetty.orbit" % "javax.servlet" % "3.0.0.v201112011016" % "compile;container;provided;test" artifacts (Artifact("javax.servlet", "jar", "jar")),
/* Apache commons libraries */
"commons-codec" % "commons-codec" % "1.7",
"commons-io" % "commons-io" % "2.4",
/* JSON support */
"org.scalatra" %% "scalatra-json" % "2.2.1",
"org.json4s" %% "json4s-jackson" % "3.2.4",
/* thumbnail library */
"net.coobird" % "thumbnailator" % "0.4.3"
),
// ignore about.html in jars (needed for sbt-assembly)
mergeStrategy in assembly <<= (mergeStrategy in assembly) { (old) => {
case "about.html" => MergeStrategy.discard
case x => old(x) }
},
scalateTemplateConfig in Compile <<= (sourceDirectory in Compile){ base =>
Seq(
TemplateConfig(
base / "webapp" / "WEB-INF" / "templates",
Seq.empty, /* default imports should be added here */
Seq(
Binding("context", "_root_.org.scalatra.scalate.ScalatraRenderContext", importMembers = true, isImplicit = true)
), /* add extra bindings here */
Some("templates")
)
)
}
)
)
}
Thanks in advance!
回答1:
There are two options of standalone deployment currently:
- Single .jar using sbt-assembly which contains runtime and webapp resources. Loading resources from the .jar file is quite slow in my experience.
- Distribution .zip file using
scalatra-sbt
plugin, contains a start shell script, the runtime resources and the webapp resources in folders.
1. Standalone JAR
For a standalone .jar file using sbt-assembly
you need to add the plugin first to project/build.sbt
:
addSbtPlugin("com.eed3si9n" % "sbt-assembly" % "0.9.0")
Then you need to modify the project build, e.g. project/build.scala
. Import the plugin's settings and keys:
import sbtassembly.Plugin._
import sbtassembly.Plugin.AssemblyKeys._
With that you can create settings for the sbt-assembly
plugin:
// settings for sbt-assembly plugin
val myAssemblySettings = assemblySettings ++ Seq(
// handle conflicts during assembly task
mergeStrategy in assembly <<= (mergeStrategy in assembly) {
(old) => {
case "about.html" => MergeStrategy.first
case x => old(x)
}
},
// copy web resources to /webapp folder
resourceGenerators in Compile <+= (resourceManaged, baseDirectory) map {
(managedBase, base) =>
val webappBase = base / "src" / "main" / "webapp"
for {
(from, to) <- webappBase ** "*" x rebase(webappBase, managedBase / "main" / "webapp")
} yield {
Sync.copy(from, to)
to
}
}
)
The first defines a merge strategy, the last one copies the static web resources from src/main/webapp
to <resourceManaged>/main/webapp
. They will be included in the final .jar in a sub-folder /webapp
.
Include the settings in your project:
lazy val project = Project("myProj", file(".")).settings(mySettings: _*).settings(myAssemblySettings:_*)
Now the launcher needs to be created. Note how the resource base is set:
import org.eclipse.jetty.server.nio.SelectChannelConnector
import org.eclipse.jetty.server.Server
import org.eclipse.jetty.webapp.WebAppContext
import org.scalatra.servlet.ScalatraListener
object JettyMain {
def run = {
val server = new Server
val connector = new SelectChannelConnector
connector.setPort(8080)
server.addConnector(connector)
val context = new WebAppContext
context.setContextPath("/")
val resourceBase = getClass.getClassLoader.getResource("webapp").toExternalForm
context.setResourceBase(resourceBase)
context.setEventListeners(Array(new ScalatraListener))
server.setHandler(context)
server.start
server.join
}
}
2. .zip Distribution using scalatra-sbt
Plugin
You need to add those imports to your SBT build.scala
:
import org.scalatra.sbt.DistPlugin._
import org.scalatra.sbt.DistPlugin.DistKeys._
Then you need to add the plugin's settings to your project. The settings are in DistPlugin.distSettings
.
You can also customize your distribution and add custom memory settings, exports and command line options. Note that those are all optional:
val myDistSettings = DistPlugin.distSettings ++ Seq(
mainClass in Dist := Some("ScalatraLauncher"),
memSetting in Dist := "2g",
permGenSetting in Dist := "256m",
envExports in Dist := Seq("LC_CTYPE=en_US.UTF-8", "LC_ALL=en_US.utf-8"),
javaOptions in Dist ++= Seq("-Xss4m", "-Dfile.encoding=UTF-8")
)
On the SBT prompt you can then type dist
. The .zip file will be in the target
folder.
回答2:
I recently ran into trouble doing this.
First, you need to make sure that jetty is available at compile time. These two lines:
"org.eclipse.jetty" % "jetty-webapp" % "8.1.8.v20121106" % "container",
"org.eclipse.jetty.orbit" % "javax.servlet" % "3.0.0.v201112011016" % "container;provided;test" artifacts (Artifact("javax.servlet", "jar", "jar")),
Need to have compile in them:
"org.eclipse.jetty" % "jetty-webapp" % "8.1.8.v20121106" % "compile;container",
"org.eclipse.jetty.orbit" % "javax.servlet" % "3.0.0.v201112011016" % "compile;container;provided;test" artifacts (Artifact("javax.servlet", "jar", "jar"))
Second, from your description it sounds like sbt-assembly is not configured correctly. You need to remove (comment out) these lines:
lazy val buildSettings = Defaults.defaultSettings ++ Seq(
version := "0.1",
organization := "de.foobar",
scalaVersion := "2.10.1"
)
lazy val app = Project("app", file("app"),
settings = buildSettings ++ assemblySettings) settings(
// your settings here
)
You will need to add ++ assemblySettings
to your foobar project immediately after scalateSettings
. Your plugins.sbt file also needs to contain the following line in it:
addSbtPlugin("com.eed3si9n" % "sbt-assembly" % "0.9.0")
For reference, I recommend against using sbt-assembly because you will most likely run into dependency conflicts that will need to be resolved with a merge strategy. Instead I suggest you use a task that collects your dependencies into a directory (examples here and here). And then add them to the java classpath using java -cp /lib/* ...
.
Third, be wary of the Jetty project in Scalatra's GitHub. I used:
import java.net.InetSocketAddress
import org.eclipse.jetty.server.Server
import org.eclipse.jetty.servlet.DefaultServlet
import org.scalatra.servlet.ScalatraListener
import org.eclipse.jetty.webapp.WebAppContext
object Jetty {
def main(args: Array[String]) = {
val socketAddress = new InetSocketAddress(8080)
val server = new Server(socketAddress)
val context = new WebAppContext()
context.setContextPath("/")
context.setResourceBase("src/main/webapp")
context.addEventListener(new ScalatraListener)
context.addServlet(classOf[DefaultServlet], "/")
server.setHandler(context)
server.start()
server.join()
}
}
Finally, it might be worth double checking your ScalatraBootstrap is in the usual place.
Hope that helps. If not I can post my entire build.scala for you.
回答3:
For an up to date answer, please refer to these two files (Credits go to Scalatra in Action book):
https://github.com/scalatra/scalatra-in-action/blob/master/chapter09-standalone/src/main/scala/ScalatraLauncher.scala
and
https://github.com/scalatra/scalatra-in-action/blob/master/chapter09-standalone/project/Build.scala