I have a java class that uses a bat file to execute commands. However I developed it in Eclipse IDE. It works fine in there. But as I export it in a jar file, it fails to find the bat file that was included.(gives me an IOException)
The file structure in eclipse is as follows
:
Project1
---->src
------>com.myproj
-------->BatFileRead.java
----md.bat
----ul.bat
md.bat and ul.bat is same level as src directory. After jarring it src folder disappears.
Could someone help me with this.
Thanks
In order to execute the command, you'll have to extract the bat file afterwards. You can't run executables which are inside jar files. Basically you'll need to open the batch file entry in the jar file as an input stream, and copy the data to a FileOutputStream on disk. You won't be able to execute it until it's a proper standalone file on the file system.
If you're already trying to extract it, chances are you're using getResource or getResourceAsStream slightly incorrectly. This is easy to do, because it depends whether you're calling ClassLoader.getResourceAsStream or Class.getResourceAsStream. The first only ever uses absolute paths (implicitly) and the second can use either absolute or relative paths. For example, in your case you'd want:
BatFileRead.class.getResourceAsStream("/md.bat")
or
BatFileRead.class.getClassLoader().getResourceAsStream("md.bat")
Have you checked that the bat files are definitely ending up in the jar file? Just list the contents with
jar tvf file.jar
to see what's in there.
Well this can be very dangerous. Be sure to use gloves when dealing with the BAT. They bite and quite painfull. Also try getting jar that has a big enough opening, although the bats will fit almost through any hole.
Good luck, and don't try this at home. This is done by professionals.
Try copying file.jar to file.zip, and opening file.zip (e.g. just double clicking, or using e.g. 7-Zip). Can you find your .bat files inside? If the .bat file isn't there, you have to add the .bat file to your Eclipse project, and rebuild in Eclipse. If the .bat file is there, but you still get an IOException opening it from you .java application, then please post the code snippet triggering the IOException, and please give a full listing of file.zip (get the listing by extracting file.zip to C:\testdir, and running dir /s C:\testdir in the command line).
Please note that Jon Skeet is right that although it is possible to open any file in the .jar file as an InputStream using java.lang.Class.getResourceAsStream and java.lang.ClassLoader.getResourceAsStream (see tutorial or find them in the Java API docs), but in order to execute a .bat file inside, you have to extract the .jar file first.
Related
I have a huge JAR file, which I created with Maven Shade plugin.
I run this with java -jar foo.jar , and my UI opens. Now I want to execute *.exe file, which is also in that JAR file, how can I do this?
I tried putting the exe to my classpath and run it from there, but after trying I found out that classpath is actually the location, where my JAR is.
Any suggestions?
Found this thing here, but is this really the best solution? Seems like alot of work, I think I have different case here, because I can define the location of exe myself and the JAR is created by me.
run exe which is packaged inside jar
Why I need this?
I want to give user a single file executable, which he can run, but my program is using the *.exe. Should I put the exe next to my jar and there will be 2 files or there is solution for my requirements?
Copying the file to a temporary location and running it is the way to go. The answer you linked to does much more work that necessary, as you can get your exe file as an InputStream and copy it to a file with a utility like Apache Commons IO FileUtils.copy(in, out)
See How do I copy a text file from a jar into a file outside of the jar? for example.
It's not about the location, it's about the fact that you need to tell your OS to run the exe and, unfortunately, you can't do that by providing a location within a jar.
Assuming that I use NetBeans 7.3 , I created a project that, in a nutshell, receiving as input a set of parameters, it returns as output a print on screen. The project is made up of a number of directories. Each directory contains a class (in file.class form). One of these directory contains an executable in C. I wrote it as the kernel of the Java project.
I built file.jar and I added it as a library in a new project. When I tried to test it, an error message made me realize that the C written program is not was automatically added to file.jar under construction.
One of my first attempt to solve this problem was to manually add the C-executable file. By using the JAR command from the terminal on my Mac, I was able to update the file.jar adding the executable in the right subfolder.
This solution is not served because, moving from project to file.jar, the relative path that leads to the execution of the C-program has changed. So I tried to change this path seeing it from the point of view of file.jar. Yet this attempt was futile.
I defer to those with more experience than me in the packaging and distribution of Java content.
As far as I know, an operating system cannot directly execute an executable that is inside a zip file (which is what a jar file actually is). It has to be first extracted.
So your program could first open its own jar file and extract the executable file into a file on disk, then run that file.
You can create an installer program, to install both the jar file and the executable file to a suitable location on the user's disk.
I've been wanting to make executable jar files with java lately. When executing my code with Eclipse it works perfectly. But when I use Eclipse to export the same code as a runnable jar, Most of my jars work except the ones that draw from separate source folders.
The jar will be made but when launched it will try and open and then just say to check to console for possible errors. I try and run the jar through the console with the command "java -jar test.jar". and It says it cannot access the jar. Any Ideas? Btw Im on a macbook pro osX. Thank you!!
picture of where my files are within eclipse
If you have a file you want to store in a jar and access from there, you don't really have a Java File any more. Look at Class.getResourceAsStream() and Class.getResource() - the first can give you an InputStream to the (used-to-be) file, the second returns a URL and can be used for things like images. Note that the file being accessed can be accessed relative to the package/folder location of the class or relative to a classpath root (by putting "/" at the front of the resource name ("/resource/funny.jpg")).
When you execute the jar from a command line, be aware that you have a thing called the "default directory"; it is a folder in which your commands execute by default. If your jar is not in the default directory, you have to specify a valid folder path to your jar to execute it.
I have created a simple class with only inherent Java dependencies (java.io, etc).
I have set up my jar file and the bat file in the same folder. The BAT simply reads:
java -jar "MyApp.jar"
pause
I have been able to run it from several different locations on my computer. But when I sent it to a coworker as a zip file, he was unable to run it by double clicking the BAT file.
The command window came back with an error
could not find the main class: MyApp.MyApp. Program will exit.
I've poked around this site but most similar errors involve use on the same computer.
Yes the other computer has Java installed 6.29
Any help much appreciated.
Two options that I can think off the top of my head:
1) He might not have extracted them both to the same directory (or) after extraction, he might have moved around the JAR file to another location.
2) His classpath does not include the current directory. Your classpath has a '.' (indicating the current directory) while his doesn't. If that is the case, you can probably modify your command to include the '-cp' switch.
In order to run a jar that way, you need a META-INF folder inside it with a manifest file inside that. The manifest file needs a main-class line that points at your class with a main(). Your IDE probably added that, but maybe in the process of extracting things he unzipped the jar file too, or something "interesting" like that.
http://docs.oracle.com/javase/tutorial/deployment/jar/appman.html
I have an app which has to read from a text file (using FileInputStream). The text file is in the directory structure relative to the class file (eg. "../textdir/text.txt"). When I run it normally (ie specifying the /bin folder containing the .class file in the cp) everything works fine. However, I somehow need to package everything into one jar and when I run the jar nothing works. The error is something like "FileNotFOund: MyJar.jar!/textdir/text.txt". I ran jar -tvf on the jarfile and the text file was indeed inside. I have read but not write access to the source code.
More than trying to solve my problem (I think there are plenty of workarounds), can someone explain to me how the whole thing work? How does the jar search for files? What if I want to read from current working directory of the command prompt instead of the directory of the .class in the jar file? Also, I recently had a similar problem with loading resources when I converted a non-jar project to a jar, how does that work?
Instead of opening the file as a FileInputStream, use getResourceAsStream which will work in both of your contexts ie. within the jar file or unpacked.