I was having trouble getting a javalin/kotlin program to build and run. Not sure if the documentation is wrong, out of date, or what. Stack Overflow, google, etc was not much help here.
Kotlin appears to be a great language for someone like me, who is java illiterate. :)
Javalin is a RESTful web container to make building CRUD apis easy. It uses jetty to run a web servlet thingy and is easy to set up routing, etc for your API. Probably want to run this on local machine and use nginx reverse proxy.
ie, nginx config
location = / {
return 302 /kt/;
}
location /kt {
proxy_set_header X-Forwarded-Host $host;
proxy_set_header X-Forwarded-Server $host;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_pass [url=http://127.0.0.1:7000/;]http://127.0.0.1:7000/;[/url]
}
NOTE: it looks like there is a bug in hubzilla, it is putting url block inside a code block.. at least in the preview... so its messing up code blocks that are supposed to have urls.
anyhow the "hello world" tutorial just gets you to the part where you type in the text editor and hit save. :) nothing past that.
First off I get an error about no main class...
% ./gradlew clean build
% java -jar ./build/libs/Jello-1.0-SNAPSHOT.jar
"No Main Manifest Attribute"
So, I guess we need a "fatJar" build with Gradle:
...
jar {
manifest {
attributes 'Main-Class': 'MAIN CLASS NAME' }
from {
configurations.compile.collect { it.isDirectory() ? it : zipTree(it) }
}
}
Figuring out what the main class is called?
in Java this is like com.wago.jello.JelloWorld
But in Kotlin, the main function is not in a class.
I could not actually find this documented anywhere, it took me awhile to figure out that the HINT is in the IDE:
Main class name is "JelloWorldKt" and that's it.
...
jar {
manifest {
attributes 'Main-Class': 'JelloWorldKt' }
from {
configurations.compile.collect { it.isDirectory() ? it : zipTree(it) }
}
}
now I got an error complaining about Missing dependency 'Slf4j simple'. Add the dependency.
so in the gradle build file,
dependencies {
compile "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
compile 'io.javalin:javalin:2.4.0'
compile "org.slf4j:slf4j-simple:1.7.25"
}
now it builds and runs:
% java -jar ./build/libs/Jello-1.0-SNAPSHOT.jar
[main] INFO org.eclipse.jetty.util.log - Logging initialized @93ms to org.eclipse.jetty.util.log.Slf4jLog
[main] INFO io.javalin.Javalin - Starting Javalin ...
[main] INFO org.eclipse.jetty.server.Server - jetty-9.4.z-SNAPSHOT; built: 2018-08-30T13:59:14.071Z; git: 27208684755d94a92186989f695db2d7b21ebc51; jvm 1.8.0_181-b13
[main] INFO org.eclipse.jetty.server.session - DefaultSessionIdManager workerName=node0
[main] INFO org.eclipse.jetty.server.session - No SessionScavenger set, using defaults
[main] INFO org.eclipse.jetty.server.session - node0 Scavenging every 600000ms
[main] INFO org.eclipse.jetty.server.handler.ContextHandler - Started i.j.c.u.initialize$httpHandler$1@482f8f11{/,null,AVAILABLE}
[main] INFO org.eclipse.jetty.server.handler.ContextHandler - Started o.e.j.s.ServletContextHandler@20322d26{/,null,AVAILABLE}
[main] INFO org.eclipse.jetty.server.AbstractConnector - Started ServerConnector@6d7b4f4c{HTTP/1.1,[http/1.1]}{0.0.0.0:7000}
[main] INFO org.eclipse.jetty.server.Server - Started @396ms
[main] INFO io.javalin.Javalin - Jetty is listening on: [[url=http://localhost:7000/]http://localhost:7000/[/url]]
[main] INFO io.javalin.Javalin - Javalin has started \o/
I am using the IntelliJ IDEA editor, When I first installed it wasn't building anything. the status/progress was just stuck saying "finalizing cache" or something. Like you could literally wait until the end of time. I discovered it's missing the slf4 jar, so you can add it in the idea.sh startup script.
The line with "slf4j-log4j12-1.7.25.jar"" :>
CLASSPATH="$IDE_HOME/lib/bootstrap.jar"
CLASSPATH="$CLASSPATH:$IDE_HOME/lib/slf4j-log4j12-1.7.25.jar"
CLASSPATH="$CLASSPATH:$IDE_HOME/lib/extensions.jar"
CLASSPATH="$CLASSPATH:$IDE_HOME/lib/util.jar"
CLASSPATH="$CLASSPATH:$IDE_HOME/lib/jdom.jar"
CLASSPATH="$CLASSPATH:$IDE_HOME/lib/log4j.jar"
CLASSPATH="$CLASSPATH:$IDE_HOME/lib/trove4j.jar"
CLASSPATH="$CLASSPATH:$IDE_HOME/lib/jna.jar"
CLASSPATH="$CLASSPATH:$JDK/lib/tools.jar"
if [ -n "$IDEA_CLASSPATH" ]; then
CLASSPATH="$CLASSPATH:$IDEA_CLASSPATH"
fi
[h1]---------------------------------------------------------------------[/h1]
[h1]Run the IDE.[/h1]
#
now it works properly.
it looks like there are a bunch of bug reports about this, i emailed their support people to check it out. maybe i'm wrong or fixed it wrong, but it seems like it solves the problem.
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