Обсуждение: pgsql-jdbc and Java

abdelkader belkadi a écrit :
> Hello,
> I developped my java project with Java NetBeans IDE,
> the code connects to a postgreSQL database using the
> postgresql-8.1dev-400.jdbc3.jar driver, the project builds and executes
> correctly when using the IDE, however when trying to use the DOS command
> line as follow:
> D:\java -jar projectpath/projectname.jar
> the following error is generated:
> Class not found !
> java.lang.ClassNotFoundException: org.postgresql.Driver
>         at java.net.URLClassLoader$1.run(Unknown Source)
>         at java.security.AccessController.doPrivileged(Native Method)
>         at java.net.URLClassLoader.findClass(Unknown Source)
>         at java.lang.ClassLoader.loadClass(Unknown Source)
>         at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
>         at java.lang.ClassLoader.loadClass(Unknown Source)
>         at java.lang.ClassLoader.loadClassInternal(Unknown Source)
>         at java.lang.Class.forName0(Native Method)
>         at java.lang.Class.forName(Unknown Source)
>         at logfilerewriter.Main.connectDb(Main.java:235)
>         at logfilerewriter.Main.main(Main.java:45)
> I checked the class path, it is correctly set.
> The error disapears if I don't call the method that connects to the
> database, which means that their is no CLASSPATH problem.

No, it means that there is a class path problem.
Could you triple check your CLASSPATH ?
What if you add " -cp path_to_postgresqldriver.jar " to your command line ?

abdelkader belkadi wrote:

> D:\java -jar projectpath/projectname.jar
> the following error is generated:
> Class not found !
> java.lang.ClassNotFoundException: org.postgresql.Driver

> The error disapears if I don't call the method that connects to the
> database, which means that their is no CLASSPATH problem.

A ClassNotFoundException means you *do* have a classpath problem,
whether you like it or not. That exception means that the JVM cannot
find the PostgreSQL JDBC driver class, i.e. it's not in the classpath.

Using -jar has the unexpected behaviour that it makes the JVM completely
ignore any CLASSPATH environment setting. So unless projectname.jar
includes the postgresql driver itself, or references it via manifest
Class-Path, this isn't going to work.

Try an explicit classname and classpath (that includes both the driver
jar and projectname.jar) instead of using -jar.

(also, doesn't the win32/dos JVM expect paths in backslash form? you've
got forward slashes above)

-O