I have just written a Java program that I now need to publish. I want to make the software easily updatable, and I therefore need your advice. The program will be used by people with minimal technical knowledge, hence usability is absolute key. The program is not open source.
The situation is this:
First time users download a zip-file containing one .jar-file and two folders that should contain the program output files (.xml-files and .png-files). I want to make it as easy as possible for the user to update the .jar (replace it with another .jar, not necessarily at run time). To my help I have a simple web-based Wordpress site that the user will view as the source of the program.
I'll list the possible solutions I've come up with:
1 (fallback solution). The user have to manually go to the Wordpress site where I'll put a separate direct download link (from Google Drive) for the .jar-file. The user then has to manually replace the .jar in the existing folder with the new one.The drawback to this is that it requires too much work from the user, and they program probably won't get updated very often.
2. Alongside the Program.jar in the zip-file the first user downloads, I place another Program-Updater.jar. This new .jar's sole purpose is to, when the user opens it, download a new version of Program.jar from the web and replace the existing one.This is better than the previous option because it requires less work, even though it's not automatic. The drawback is that I need one more .jar which can confuse the user, and most importantly I have no way of updating the Program-Updater.jar.
3. Java Web Start.I've tried reading up on how this works, but I'm wondering if there is a way to get it to work. One possible problem is that I can't really access the host, and to be able to set up the .jnlp the correct way I think you need this. I'm also wondering how the program's file structure would be (is the .jar even placed on the user's computer?) and if this could confuse the user. Also how to make it always work offline.
4. Suggest your own solution!
Any input on this matter would be greatly appreciated, and I'll gladly give more info than I already have.
Cheers
Getdown was the way to go; it is extremely easy to use.
I'll put the .zip on Google Drive with a direct download link to it on my Wordpress site.
The files used by getdown are placed in and downloaded from my public git repo.
Related
I'm working on an application that generates a series of files based on user input that would be later uploaded to a cloud service.
It is important that these files remain intact (prevent modification or deletion) before they are uploaded.
What would be the best way to accomplish this? I could work with Windows only solutions. I know that a sufficiently motivated advanced user would be able to do it anyways but I'm looking for solutions to obscure or just make it harder than 'Select all > Delete'.
All these generated files will be within the same folder.
Thanks in advance!
Edit: I previously stated that I didn't mind the files could be read but that would enable copying and storing them somewhere else and that is undesirable too.
I have been coding for about a month and I have found ways to adapt around ever problem but one. The problem as you can probably see by the title is how to make a way to make game saves. I am currently creating a very simple game that has about 5 classes of my code and maybe 2 of Java Swing GUI.
I know how I would like to go about the saving process but I have no idea how to do it in my code. How I would like to go about doing this is by making the code print a Number or Integer to a file to represent a Level. For example if you completed level 1 the number in the file would be 1. I have tried some templates for this but none of them work.
I understand how to write to a file but my problem is reading it from a jar or even creating a file then reading it from a place on the computer. I need to know how to find a file URL for different computers because some use Docs and Settings and other Users. Please could someone help.
Since the jar is read only, it can only contain the 'default settings'. See this answer for the general strategy to deal with such a embedded-resource.
Speaking of which (embedded resources) see the info. page for more details on how to access them.
Here is an example of storing and reading a Properties file from the 'current directory'.
As mentioned by #MadProgrammer though, it is safest to put the settings file into a (sub-directory) of user.home, as seen in this answer.
But a properties file is just one option. You might also serialize an object, or write the file in a custom format that your app. knows how to read, for the first two off the top of my head.
Besides 'serialize (in some form) in a File', there is also the Preferences API, or for desktop applications launched using Java Web Start, the PersistenceService. Here is a demo. of the service.
I need to know how to find a file url for different computers because
some use Docs and Settings and other Users
The System property user.home points to the user's home directory
File userHome = new File(System.getProperty("user.home"));
I'm making a game, in Java, that has these following important features:
1) Connects to a remote Server (which i made), and will check for updates and install them if necessary
2) is NOT A SINGLE .JAR FILE (ie. has multiple .jar's and other things, such as .png, .wav, etc)
3) JAVA WEB START IS NOT AN OPTION, AS I WANT TO MAKE THIS ALL MYSELF
keeping the things above in mind, i have run into a problem. i have no clue how to implement a multiple "patch" update system. currently i have 1 .txt file, that the server reads from, and sends the files listed in the .txt to the client, which then moves them into place. The problem is, that is only useful for maybe 2 updates. I'm looking for a more useful, long term solution, and i need some help. here are some of the things i've thought of:
1) have a zip folder named after each version (problem: how would the client get ALL of the most updated files
2) have a .txt file INSIDE of each jar containing the version (problem: cant do that with png's or wav's, and i dont know how i would read the txt file to begin with)
i really need some help, i've tried googling it, i've thought about it for going on 3 weeks now, and cannot think of anything.
QUESTION: how would i make a game/program update with multiple patches?
Firstly, the best solution by a long, long way is to use Webstart / JNLP.
But if you insist on not using it (for whatever reason then) then it is technically possible. However:
It is messy and complicated.
It will either be very inefficient ('cos you have to load the entire program each time the user), or the user has to trust you enough to install your program with permissions that will allow it to install random stuff on his machine without notice.
The way to do it is to split the game into a launcher part and an application part. The launcher needs permissions to write and delete (non-temporary) files, and fetch stuff from the internet. It "calls home" to find out the latest version(s) of the application files, and then downloads and installs them. It has to cope with all sorts of error conditions, and it needs to make sure that nothing can trick it into installing bad stuff on the user's machine, etcetera, is someone spoofs your update service.
Of course, JNLP takes care of all of this, and lots more besides. People are going to be more willing to install the JNLP infrastructure that yours ... which might be insecure, or actively nasty (for all they know). (I for one wouldn't install a self updating application on my machine unless it was supplied by a company with impeccable credentials.)
I think you need here JNLP framework.
JNLP provides followed things:
allows to user to download jars from server
on launch verifies if application need to update
runs on local JVM
Actually, every java application you can convert to JNLP. Just to sign on all jars that your game contains, create executable jar from your game and create single Web page from where you can download your game
I have developed a command-line (read: no GUI) Java application which crunches through numbers based on a given dataset and a series of parameters; and spits out a series of HTML files as resultant reports. These reports hold a large amount of data in tables, so in order to give the users a easy and quick overview of the results, I utilized the JUNG2 library and created a nice graph.
Here's where it gets interesting; since I would like the graph to be interactive it should be deployed after the application has run and files are generated, whenever the user wants to view the reports. I decided to go with an applet based deployment, however I am not too happy with the current setup due to the following reasons:
I want to make the software as simple to use as possible (my users won't be tech-savvy, and even tech-intimidated in most cases). I would really like to distribute one JAR only, which forced me to put the applet with everything else it needs in a package in the same JAR as the main application.
The applet and the main application need to communicate the results, so I create a xML-based report which is used to hold information. As long as the files are on a local machine and are not moved around it all works fine. Unfortunately I also need the files to be moved around. A user should be able to take the "results" folder to a USB stick, go anywhere plug the stick to another computer and be able to use the report as he/she likes.
For the time being the applets are implemented with the following html code:
<applet code="package.myapp.visualization.GraphApplet.class"
codebase="file:/home/user/myApp"
archive="myApp-0.2.6-r28.jar"
width="750" height="750">
<param name=input value="results/test_name/results.fxml">
</applet>
As you can see this applet will not work if the parent folder is moved to another location.
As far as I know I have a couple of alternatives:
a) Change codebase to point to an URL on our webserver where I could put the jar file. This however creates the problem with permissions, as the applet will not be able to read the results file. Alternative is to upload the results file to the server when the user wants to visualize the graph, although I am not sure if that's a good option due to server security and also if it could be made so that upload happens automatically without bothering the user.
b) I can use a relative path on the codebase attribute, but then the whole folder hierarchy needs to be intact upon copy. This could be a last resort, if I cant come up with a better way to do it.
c) change the deployment method (would like to avoid this alternative to not spend more time on the development phase)
Any ideas? Am I missing something? How could I tackle this problem?
Thanks,
I'm not sure I entirely understand your use-case, but from what I do understand, I would suggest this:
Dump the applet for an application launched using Java Web Start. Have the JNLP file declare a file association for the fxml file type. When the user double clicks an fxml file, it will be passed as an argument to the main(String[]) of the JWS application.
A sand-boxed JWS application can gain access to resources on the local file system using the JNLP API. Here is my demo. of the JNLP API file services.
I am developing a small game in Java and I am shipping it as a single Jar file. I want to store the high scores/best times for that game somewhere. Instead of storing it in a separate file, I would like to store it in the application itself (inside the Jar) so that its not lost. Is this possible at all ? If so, how to do it programatically.
Java does not give you tools to modify the JARs which are currently run. If you really want to do it, you have to guess the location of the JAR by yourself (which might reside on a read-only filesystem) and modify it the same way you would modify any archive file.
Bottom line: it's a very bad idea, don't do it! See this question for a much more reasonable solution.
Nothing is impossible, but storing it in the jar file would make it very complicated. You might also end up with unwanted side effects like "Permission Denied" errors when the jar is owned by another user. Virus scanners might get nervous when they see jar files change without reason, etc....
I would look to the Preferences API for storing this kind of info.
I think it is a bad idea to try and store anything in the jar file. Another option is to have a web based service offered to the people playing with your game. The game could connect through a web service to your hosted server and then store everything centrally there. Not sure if it is exactly what you want but it's just an idea. It would also allow people to compete with each other.
Java JAR file is a ZIP-Archive, so you could possibly access it with standard ZIP-Tools and just extract one hisghscores.txt file, modify it and then pack it back again.