Class.forName(Class) in a specific directory? - java

While testing a program I am developing that writes to a SQLite database, I noticed that if I moved my sqlite.jar file to a sub-directory, Class.forName("org.sqlite.JDBC") throws the ClassNotFoundException. Is there a way that I can change the directory that Class.forName("org.sqlite.JDBC") is looking in so that I can store the file where I want it?

It looks like the classpath is set to work with that location. If you are using an IDE, add the library to your build path in your project properties and then execute your code. The IDE will do the rest of the things you need to do.
If you are working with classpath setup, you should not move your files from the classpath where the class files are specified and your program will look for its desired class to load.

Related

Export to JAR with external JavaPOS Files

I've currently finished my project, but can't get it to work when it is exported. I use JAXB to read and write XML Files and also have dependencies on other external Folders, which are needed to use a POS-Printer.
I've managed to link my external XML Save-Files with absolute paths, but not with relative paths. So that worked, although not the way i wanted. Yet, using the external class folder for the printer didn't work at all.
This means, that in my Eclipse Project Build Path i've added a class folder, which contains all of these needed files (which are not only jars, so adding them one by one wouldnt work). So exporting my project to a jar either includes all the files into the jar itself, or doesnt include them at all.
Everything works perfectly in Eclipse, but not when i export it.
My folder structure looks like this:
src
/model
/view
/control
data
/articles.xml
/...
JavaPOS <--- needed folder with all its files
/jpos.xml
/xerxers.jar
/swt-..-.dll
I've tried:
InputStreams is = getClass().getResourceAsStream(url);
absolute paths
manipulating the manifest file and/or jar structure
runnable and non runnable jars with nearly every combination of options
putting the files inside the library "by hand"
changing the build path of the project
My Question is:
How do i get my jar-file to know where these files are?
EDIT:
Do you think Maven or an Ant file could solve my problems? I don't have any experience with those.
The Problem was, that i had more than one JRE installed and that the one eclipse was using, had all the dll files, but the other ones didnt have it. So i had to add them manually, because reinstalling the drivers of the printer didnt change anything. Gotta fix that somehow, but right now it works and that is all i wanted.
Turns out i didn't even need that Folder, just needed one file out of it and the missing dlls.

Accessing a file within Java project

I have a Java project which uses a third party application. I have the license file (.lic format) stored in the resources folder. Upon running the Ant script, it will copy this file into the /lib/jar directory as it rolls up the project into a Jar file to use on the server. This is where I will need to access the file when running the system live. Here is how the folder structure looks
MyProject
src
package
AccessingClass.java
resources
File.lic
lib
jar
File.lic (upon copy from Ant)
I am not sure the best way to do this so any suggestions other than how I have been trying will probably be helpful. The 3rd party project has a method in a class like License.setLicense(), which can either take a String to the location or an InputStream of the file.
I have been playing around with feeding it an InputStream, but always get a null value when calling getClass().getResourceAsStream(). Here is everything I have tried:
getClass().getResourceAsStream("../../../lib/jar/File.lic");
getClass().getResourceAsStream("/File.lic");
And as a backup I also tried (for local builds I figure I would try the resource folder):
getClass().getResourceAsStream("../../../resources/File.lic");
getClass().getResourceAsStream("/File.lic");
Is there a better method to perform this action? Or would someone be able to tell me why what I am trying is failing? Thanks ahead of time.
Are you running this code standalone or in IDE env looks like classpath issue. If you are running at command prompt you have to set classpath to lib dir if in ide make sure you resources dir is in classpath.
First, you need to ensure that the JAR is added in your class path.
Below should work.
InputStream inputStream =
getClass().getClassLoader().getResourceAsStream("/resources/File.lic");
Assuming File.lic is placed in root folder of the jar.

How to include sqlite db file into jar in netbeans?

I use sqlite in my java application. When I run it from Netbeans, it works well. The sqlite db file is located in the root project directory (same level as build.xml).
This is the code to access the database file:
DriverManager.getConnection("jdbc:sqlite:database.db");
However, when I build the project, and run the jar file outside netbeans, I always get this error: no such table: table_name
My question: where is the correct location to put the "sqlite db" file? Is it possible to package it inside the JAR file?
I have tried to package my application into a single JAR file (similar to Eclipse's FatJar), but I still get that error. In this case I modify the build.xml as explained in this blog:
Netbeans single JAR
I also tried to create a database folder in the src directory and then put the db file inside the folder (src/database/database.db) and access it using
DriverManager.getConnection("jdbc:sqlite:src/database/database.db");
I can run it inside netbeans. But when I run it outside, I got this error:
path to 'src/database/database.db':C:\Windows\system32\src' does not exist
I know there are similar questions to this in stackoverflow, but most of them don't have a concrete solution. Let me know if someone has found a better one.
Thanks a lot.
Problem solved!
I made a mistake in the way I execute the JAR file. Previously I run the JAR file by right click on it and open it with Java SE binary. I need to do this because in my PC the default program to open JAR file was set to another software.
It turned out that I have to set the default program to Java SE Binary and the double click the JAR file in order to run my application. Using this way I can run and access the sqlite db file without a problem.
I hope this can help others who may get the same problem as I had.
probably you need to point your app to include your app base directory in the classpath.
the command to run your app should be something like:
java -cp . YourAppMainClass
the "-cp . " is the command option that tells java to include current directory in the classpath.

HP Service Test - Call Java Class service - having class path issues

I am currently using HP Service Test 11.10 to test a call to a web interface, but as part of this test I'm adding some data to an oracle Database, which by default HPST does not support. HPST does support calls to a java class, so I'm attempting to call a Java class in a .JAR file. I have placed this .JAR file in the directory with my test solution. When I add a step to Call Java Class I can select and run the file just fine, but I'm having a problem where I cannot move my test solution to a different directory without getting a java.lang.NoClassDefFoundError when I run my test.
As near as I can tell, it's trying to call the specific path for the .JAR when I add it (I.E. something like c:\temp{test directory}, even though I may have moved it to c:\users{user name}\workspace{test directory}). How can I change this so that it always looks in the same directory as the test solution for this .JAR file?
....
From the HP Software Solutions Community forum:
Hello, You are right, the path of the .jar file is indeed preserved
within the test as it is translated to code. This path cannot be
modified, and there's no way to add jar paths relatively to the test
path.
But still, one workaround I can think of is to include this jar in
what we call InternalJavaClasspath:
You can define a new path to that jar of yours within
InternalJavaClasspath.dat located under
{hp_service_test_installation_folder}\dat And then you must put this
jar in a subfolder under the installation folder.
The common location is: bin/java - you can create a folder here called
MySpecialJars and the respective line in the dat file will be:
bin/java/MySpecialJars/MySpecialJar01.jar

Problem with resources location difference in eclipse and JARs

I wrote a program that is based completely on a single text file: I read the file, store the information, then search the information, etc. So, for the program to work, the file just has to be present and detectable by the program.
I use eclipse, so I put the file is in the default resources map (src/main/resources). At the start of my program I create the file:
private static File textFile = new File("src/main/resources/TEXT.TXT")
However, when I try to package my program using Maven, I get a JAR in which all class and resources files are present in the same folder; my program stops working since it cannot find the file anymore.
Any help on how to deal with this problem? I`d prefer a situation in which my program works in eclipse and as a JAR, but as a JAR only would be alright as well.
You can use ClassLoader.getResourceAsStream to load it from the classpath (or getResource to get the URL of the file).
Thread.currentThread().getContextClassLoader().getResource("TEXT.TXT")
This works as long as src/main/resources is on the classpath in eclipse. (The maven eclipse plugin includes it by default.) The file has to be in the jar file to work outside of eclipse.
Nice suggestions, this works perfect in eclipse itself: the correct location of the file is returned and I can use the file to do whatever I like.
When opening the program as a jar, there is still a problem. The getResource method returns a location that looks like the right one:
/something/something/something/something/workspace/program/target/program-0.0.1.jar!/TEXT.TXT.
However, when I convert this url to a string, use that string to create a file object and use this file object in my program, I get the following error:
java.io.FileNotFoundException: file:/something/something/something/something/workspace/program/target/program-0.0.1.jar!/TEXT.TXT (No such file or directory)
So, the getResource method does find the file, but the program somehow can't use it..

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