Tomcat
Tomcat is a web server with a built-in Java Servlet, JavaServer Pages, Java Expression Language and Java WebSocket interpreter that can also serve static HTML pages.
This How-To describes how to set-up Tomcat to deliver static HTML pages as well as prepared WAR packages.
Installation
Java
Tomcat requires the Java Runtime Environment, which is available from the Alpine repository as openjdkN (where N stands for the version). Install the most up to date version of Java, 8 at the time of writing (September 2017).
apk add openjdk8
Tomcat
Tomcat has to be downloaded from the Apache Tomcat homepage. You need the Binary Distribution Core, download it, save it in a place where you can easily find it and extract it into a folder of your choice. As most other manuals for Tomcat use /usr/local/tomcat, this manual will assume that Tomcat is extracted there as well and call it $TOMCAT$ from now on.
cd /usr/local/tomcat
tar xvzf apache-tomcat-9.0.0.M26.tar.gz
Testing
Installation
Tomcat should run without any further configuration. Switch to $TOMCAT$/bin and execute the following command:
cd /usr/local/tomcat/bin
sh catalina.sh version
You should see a list of folders, the installed tomcat version, OS name, processor architecture and so on. If this fails, either the installed version of tomcat is somehow incompatible with the installed version of Java or one of the two programs was not properly installed.
Server
If the first test succeeded, you can test the server itself by running catalina.sh with the start command.
sh catalina.sh start
Several lines of text should appear, the last line should read Tomcat started.
Now, point a browser on the same computer that Alpine runs on to http://127.0.0.1:8080/. You should see a page that says If you are seeing this, you successfully installed Tomcat. Congratulations!.