BKM向最终用户交付基于Web的Java应用程序+ Jetty + JRE

Question

I have a Java application with a web-based UI (using Vaadin framework). I want users to get the app and run on their local machines. Some users can be not very technical, so need to make this as simple and foolproof as possible for them.

Possible solutions:

1. Create a distributive with the webapp + Jetty + batch and shell scripts to start the app. maybe include JRE too. The User Story will be: download some ZIP file, unpack and run "start.bat" or "start.sh". The script will start Jetty and maybe launch a web browser with "http://localhost:8080/myapp" URL. There should be no magic with "installing JRE" or "what's your Java Home" or "Your JRE is too old", etc... This would scare the hell out of many non-technical people. Difficulties here: what if the machine does not have JRE? I'd like to avoid creating 3 different distributives with JREs (for Win/Linux/MacOS). Packaging all 3 JREs into the same distributive seems like an overkill.

2. Another approach I see is using Java Web Start. My app would be downloaded through JWS with Jetty JAR as a dependency and start the embedded Jetty in this case. The User Story: click a button on some website to launch the app locally. I remember having problems with using JWS from behind a proxy ~5 years ago: the dependencies could not be loaded. Not sure if it's still a problem. I haven't used JWS since then, so I'm very familiar with it. Another problem with JWS is that it will require people to have internet connection to launch the app (at least for the 1st time or maybe every time), which is not always possible (some organizations can't be connected to the Internet). AFAIK, the last JWS suggests installing JRE if it's not there yet, so this should be easy for end-users. That's probably it for the potential issues with JWS (?).

3. Finally, the last approach is to pack everything with something like launch4j or InstallShield or whatever. Hopefully those programs are capable of installing JRE is it's not present yet and also can run in headless mode (for servers).

So far option 2 looks the easiest for most users, assuming that JWS can do what I need.

So, my questions are these:

• Which additional pitfalls do you see with these 3 solutions?
• Which one would you prefer in my case?

Answer 1

I prefer a combination of the solutions 1 and 3. I mean:

• First, build a jar with an embedded Jetty that runs your webapp. This jar must have a main class (that starts an embedded Jetty) and a MANIFEST.MF configured with the "Main-Class" property, so this jar can be runned with: " java -jar myEmbeddedWebApp.jar ".
• Then, use launch4j to build an exe wrapper for that jar, eg myEmbeddedWebApp.exe