问题
I have followed this very basic tutorial for setting up a WebSocket endpoint in Java: http://www.oracle.com/webfolder/technetwork/tutorials/obe/java/HomeWebsocket/WebsocketHome.html
Heroku, however, expects me to rely on Play Framework: https://devcenter.heroku.com/articles/play-java-websockets
My question is: how could I deploy the same without any additional frameworks and what procedure should I go through in order to make things work?
回答1:
The problem you had was this:
The tutorial you followed was made for the GlassFish Application Server but Heroku only supports Tomcat 8 and Jetty. See here: https://devcenter.heroku.com/articles/war-deployment
But don't worry, I ported and tested the tutorial to run with Tomcat 8.
I also added the glassfish implementation of the javax.json specification. (Make sure to download the implementation and not the spec interfaces only) You can find it here: http://central.maven.org/maven2/org/glassfish/javax.json/1.0.4/
I also noticed why maybe your index.html didn't work locally: I think it was because the WebSocket URL was hardcoded in the websocket.js file. I have taken the liberty to fix this by making it dynamic.
Here is the complete NetBeans 8.0.2 project:
http://ray.hulha.net/WebsocketHome.zip
Here is the best way to create a war file from inside NetBeans 7 or 8:
There is one catch however, the Tomcat 8 on Heroku is missing the websocket addon.
But no worries, you can added it manually to the war file. Here are the steps:
Download the Tomcat websocket addon here:
http://central.maven.org/maven2/org/apache/tomcat/embed/tomcat-embed-websocket/8.0.29/tomcat-embed-websocket-8.0.29.jarThe war file is really just a zip file. So I used 7-zip to open the war file. Then navigate to the WEB-INF/lib folder inside the war file.
Copy the jar into the war. Drag and Drop the tomcat-embed-websocket-8.0.29.jar into the lib folder of the war file inside 7-Zip.
Z-Zip will ask if you really want to copy the jar into the war file. Say Yes.
Here is the compiled war file complete with the tomcat-embed-websocket-8.0.29.jar ready to deploy on Heroku: http://ray.hulha.net/WebsocketHome.war
I used this command to deploy it:
heroku war:deploy WebsocketHome.war --app websockethome
Make sure to replace the app name in the end with your app name.
And here is the working result: http://websockethome.herokuapp.com/
回答2:
Heroku does not require Play framework to use Websockets. That is just an example. As long as your app from the Oracle tutorial binds to $PORT it should work.
来源：https://stackoverflow.com/questions/49841902/how-to-deploy-and-access-a-java-websocket-endpoint-on-heroku-without-any-additio