I have a few projects which run using Jython 2.7b1 where I add the jars (in fact all the jars in a directory) by doing this:
set CLASSPATH=.;"%SYSADMIN%\resources\java jar files/*"
set JYTHONPATH=...
C:\jython2.7b1\jython myproj\__main__.py
But my latest project is using 2.7.0FR and this "set CLASSPATH" approach doesn't seem to work. I then tried this:
D:\apps\jython2.7.0\bin\jython -Dpython.path="%SYSADMIN%\resources\java jar files/*" my_latest_proj\__main__.py
... but it didn't work. Then I wanted to see whether I could load an individual .jar:
D:\apps\jython2.7.0\bin\jython -Dpython.path="%SYSADMIN%\resources\java jar files\lucene-analyzers-common-4.6.0.jar" my_latest_proj\__main__.py
This didn't work either: the following line
from org.apache.lucene.analysis.fr import FrenchAnalyzer
leads to the following error: "No module named apache"... nor is there any "unpacking" of the jar as you typically see with Jython the first time you use a jar.
Finally I tried this:
set CLASSPATH=.;"%SYSADMIN%\resources\java jar files\lucene-analyzers-common-4.6.0.jar"
... same thing: "No module named apache"
NB I have no trouble getting jars to work from within my project when running it under Eclipse.
Can anyone tell me what I'm doing wrong?
Aha...!
1) It appears that with Jython2.7.0FR you have to use forward slashes in paths in the CLASSPATH, even in a Windows OS. This appears to be a change relative to 2.7b1...
2) I also seem to find that paths with spaces are to be avoided... previously I could enclose such a path in quotes and it would work OK. This seems not to work any more.
Any comments from the Jython "High Command" would be welcome...
I ran it in cmd and it said no main manifest attribute in, JGame2.jar
how do i show it where the main is?? it works fine in eclipse.
For
java -jar x.jar
to work, the jar file must contain a META-INF/MANIFEST.MF file, and this file must contain an entry for the main class. You can add a manifest in Eclipse. Note that any dependencies must also be accounted for, either by:
a class path in the manifest
-cp on the command line
use of some tool to combine to one jar
Eclipse is just an IDE, you might consider learning to use an actual build tool such as Maven or Gradle or Ant to allow you to repeatably build usable results.
I have two java files. They run fine in NetBeans, but I have to compile them in javac, and run them on a unix machine since I'm connecting to a database on my school's server.
I've been searching online but everything is too specific, and I'm not too familiar with NetBeans.
What I'm doing is copying those two java files, and a .form file to a directory on my school's server, and then try to compile the two java files using javac. However, I'm assuming that it doesn't compile because it's missing all the information from the .form file?
I'm getting 100 errors when compiling the one of the java files, and they look something like this:
CARTSJFrame.java:380: package org.jdesktop.layout does not exist
.add(jPanel9, org.jdesktop.layout.GroupLayout.PREFERRED_ SIZE, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, org.jdesktop.layout.GroupLay
My guess was that it has something to do with the .form file that I can see in my NetBeans project directory.
I've looked at previous questions about this but still haven't been able to figure this out. Any help is appreciated.
You are running into compilation errors because NetBeans includes a jar in your project's classpath automagically when you compile and run the project.
NetBeans uses the dot-form file to help it generate code for the layout. It is not used at compilation time.
There are a couple strategies that you can follow to resolve this problem:
Get the jar that has the classes...
http://www.findjar.com/jar/net.java.dev.swing-layout/jars/swing-layout-1.0.1.jar.html;jsessionid=252692AC0FBE9421C9436A748744ACED... and include that jar in your
classpath at compile and runtime.
Convert the code in your project to
use the javax.swing.GroupLayout.
This is a 'standard part' of Java SE 6. This SO answer covers how to convert between
org.jdesktop.layout.GroupLayout and
javax.swing.GroupLayout in
NetBeans.
I think your problem is that javac doesn't know where to find that library.
A typical Java project uses many libraries. Netbeans uses a folder "lib" to store those libraries and also some configuration files to automatically set the classpath. The classpath is a environment variable that Javac uses to 'know' where are the libraries.
When you use javac to compile the java files you need to provide the CLASSPATH variable first. Write all you dependencies.
An example:
Project/compile_all.sh
export CLASSPATH=$CLASSPATH:"lib/jopt-simple-3.2.jar":"lib/commons-io-2.0.jar"
javac src/*.java
Now you just need to run
sh compile_all.sh
And it compiles all you .java files
I've got a relatively large Java application that would benefit from a bit of Python love. To that end I've been working on getting it up and running in Jython. My current roadblock is getting the classpath right.
I've taken two approaches to setting the classpath:
Using a shell script, I've built up a list of jars and executed java -cp ${CP} -jar jyton.jar where $CP is a list of the jars needed for my app. This doesn't seem to work. I'm unable to import any classes from these jars, getting only ImportError: No module named apache instead.
Using a bootstrap python script, i've created a list of paths using glob, and appended them to the current path using [sys.path.append(path) for path in JAR_LIST]. This seems to work correctly; I can now import any of the classes I need to from the included jars.
The above is a bit confusing as most information I've been able to find has steered towards using $CLASSPATH and -cp to added your jars, but I can't get that to work. So the question so far: Is #2 the proper way to add dependancies to your classpath when using Jython?
The main reason I question my methods is because I'm still having problems fully utilizing my application. A number of places in my app reverences resources using relative URLs : classpath:some-critical-file.xml
some-critical-file.xml and a number of my classes reside within the same jar. I'm able to import classes from that jar, but any attempts to load my xml with classpath:some-critical-file.xml results in a java.io.FileNotFoundException
Any insight as to why my classes are available but relative paths to resources using classpath: are not would be much appreciate. I'm at a loss at this point.
I've run into a little classpath weirdness myself lately. Have you tried the old school approach of:
CLASSPATH = ${CLASSPATH}:your.jar
export CLASSPATH
jython your_script.jy
If you're invoking the standalone jar using java -jar then from the Java Documentation ...
-jar
When you use this option, the JAR file is the source of all user classes, and other user class path settings are ignored.
So it it not possible to add anything to the classpath when using -jar. See this answer for a solution - basically add the jython.jar to the classpath (either using -cp or CLASSPATH) and run the org.python.util.jython class directly.
There is a VERY similar question to mine but in my case I don't have any duplicate jars in my build path, so the solution does not work for me. I've searched google for a couple of hours now, but none of the solutions I've found there actually resolve my issue. I'm creating a web site with some database connectivity for a homework. I'm using a MySQL database, developing in Eclipse and running on Windows.
I keep getting java.lang.ClassNotFoundException: com.mysql.jdbc.Driver with the following code:
import java.sql.*;
//...
public void someMethodInMyServlet(PrintWriter out)
{
Connection connection = null;
PreparedStatement query = null;
try {
out.println("Create the driver instance.<br>");
Class.forName("com.mysql.jdbc.Driver").newInstance();
out.println("Get the connection.<br>");
connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "secret");
query = connection.prepareStatement( "SELECT * FROM customers");
//...
} catch (Exception e)
{
out.println(e.toString()+"<br>");
}
}
//...
When I run the above code I get the following output:
Create the driver instance.
java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
It doesn't get past the Class.forName... line and I can't figure out why! Here is what I did:
Download mysql-connector.
Put it in my MySQL folder C:\Program Files\MySQL\mysql-connector-java-5.1.12\mysql-connector-java-5.1.12-bin.jar.
Opened the project properties in Eclipse.
Add External Jar to my Build Path and I selected mysql-connector-java-5.1.12-bin.jar.
Every time I attempt to use the servlet I get the same error regardless if I have the jar in there or if I don't. Could you help me figure this out?
As for every "3rd-party" library in flavor of a JAR file which is to be used by the webapp, just copy/drop the physical JAR file in webapp's /WEB-INF/lib. It will then be available in webapp's default classpath. Also, Eclipse is smart enough to notice that. No need to hassle with buildpath. However, make sure to remove all unnecessary references you added before, else it might collide.
An alternative is to install it in the server itself by dropping the physical JAR file in server's own /lib folder. This is required when you're using server-provided JDBC connection pool data source which in turn needs the MySQL JDBC driver.
See also:
How to add JAR libraries to WAR project without facing java.lang.ClassNotFoundException? Classpath vs Build Path vs /WEB-INF/lib
How should I connect to JDBC database / datasource in a servlet based application?
Where do I have to place the JDBC driver for Tomcat's connection pool?
JDBC CLASSPATH Not Working
Since you are running it in servlet, you need to have the jar accessible by the servlet container. You either include the connector as part of your application war or put it as part of the servlet container's extended library and datasource management stuff, if it has one. The second part is totally depend on the container that you have.
The others are right about making the driver JAR available to your servlet container. My comment was meant to suggest that you verify from the command line whether the driver itself is intact.
Rather than an empty main(), try something like this, adapted from the included documentation:
public class LoadDriver {
public static void main(String[] args) throws Exception {
Class.forName("com.mysql.jdbc.Driver");
}
}
On my platform, I'd do this:
$ ls mysql-connector-java-5.1.12-bin.jar
mysql-connector-java-5.1.12-bin.jar
$ javac LoadDriver.java
$ java -cp mysql-connector-java-5.1.12-bin.jar:. LoadDriver
On your platform, you need to use ; as the path separator, as discussed here and here.
Place mysql-connector-java-5.1.6-bin.jar to the \Apache Tomcat 6.0.18\lib folder. Your problem will be solved.
What you should not do do (especially when working on a shared project)
Ok, after had the same issue and after reading some answers here and other places. it seems that putting external lib into WEB-INF/lib is not that good idea as it pollute webapp/JRE libs with server-specific libraries - for more information check this answer"
Another solution that i do NOT recommend is: to copy it into tomcat/lib folder. although this may work, it will be hard to manage dependency for a shared(git for example) project.
Good solution 1
Create vendor folder. put there all your external lib. then, map this folder as dependency to your project. in eclipse you need to
add your folder to the build path
Project Properties -> Java build path
Libraries -> add external lib or any other solution to add your files/folder
add your build path to deployment Assembly (reference)
Project Properties -> Deployment Assembly
Add -> Java Build Path Entries
You should now see the list of libraries on your build path that you can specify for inclusion into your finished WAR.
Select the ones you want and hit Finish.
Good solution 2
Use maven (or any alternative) to manage project dependency
Just follow these steps:
1) Install eclipse
2) Import Apache to eclipse
3) Install mysql
4) Download mysqlconnector/J
5) Unzip the zipped file navigate through it until you get the bin file in it. Then place all files that are present in the folder containing bin to C:\Program Files\mysql\mysql server5.1/
then give the same path as the address while defining the driver in eclipse.
That's all very easy guys.
If the problem still persists,
Put the-
mysql-connector-java-5.0.8-bin jar in a place inside your Tomcat->lib->folder (No matter where you've installed your Tomcat). And change your environmental variable (Done by clicking Properties of Mycomputer -Advanced system settings- Environmental variables-And set a new variable name & variable values as the place where your lib file resides.Dont forget to enter a ; at the end of the path)
If still problem persists
Try downloading commons-collections-2.0.jar (http://www.docjar.com/jar_detail/commons-collections-2.0.jar.html) and paste the jar in the same place where your mysql jar resides (ie) inside Tomcat-lib.
Clean your project-Stop your server- Finally try to run.
Many times I have been facing this problem, I have experienced ClassNotFoundException.
if jar is not at physical location.
So make sure .jar file(mysql connector) in the physical location of WEB-INF lib folder. and
make sure restarting Tomcat by using shutdown command in cmd.
it should work.
The only solution worked for me is putting the .jar file under WEB-INF/lib . Hope this will help.
assuming your project is maven based, add it to your POM:
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.26</version>
</dependency>
Save > Build > and test connection again. It works! Your actual mysql java connector version may vary.
Put mysql-connector-java-5.1.38-bin.jar to the C:\Program Files\Apache Software Foundation\Tomcat 7.0\lib folder.by doing this program with execute
My issue was a little different. Instead of jdbc:oracle:thin:#server:port/service i had it as server:port/service.
Missing was jdbc:oracle:thin:# in url attribute in GlobalNamingResources.Resource. But I overlooked tomcat exception's
java.sql.SQLException: Cannot create JDBC driver of class 'oracle.jdbc.driver.OracleDriver' for connect URL 'server:port/service'
for this error:
java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
you need to:
Import java.sql.*;
Import com.mysql.jdbc.Driver;
even if its not used till app running.