Обсуждение: begginer question jdbc not working

Hi I am very new to Java.

I am having trouble getting connection to a database.  I installed the
Debian package 'libpg-java' version '8.0-312-1'.

I can't seem to get it to work.  I copied the 'basic.java' example from
'/usr/share/doc/libpg-java/examples/example' to the '/tmp' directory.
Then tried to compile and run it.
$ javac basic.java
basic.java: In class 'example.basic':
basic.java: In method 'example.basic.main(java.lang.String[])':
basic.java:206: warning: The method 'setLogStream' in class
'java.sql.DriverManager' has been deprecated.
DriverManager.setLogStream(System.err);
                             ^
1 warning

$ java basic
java.lang.NoClassDefFoundError
    at java.lang.VMClassLoader.nativeDefineClass (VMClassLoader.java)
    at java.lang.VMClassLoader.defineClass (VMClassLoader.java:94)
    at java.lang.ClassLoader.defineClass (ClassLoader.java:673)
    at java.security.SecureClassLoader.defineClass
(SecureClassLoader.java:108)
    at java.net.URLClassLoader.findClass (URLClassLoader.java:926)
    at java.lang.ClassLoader.loadClass (ClassLoader.java:360)
    at java.lang.ClassLoader$1.loadClass (ClassLoader.java:1285)
    at java.lang.ClassLoader.loadClass (ClassLoader.java:304)
    at java.lang.VirtualMachine.main (VirtualMachine.java:99)

Any help in getting this to work would be appreciated.

Regard Neil.

Neil,

Just a shot in the dark, but I'm guessing you don't have your
classpath set to the current directory.

ie CLASSPATH=./

that will find basic

then you will need to add postgresql to it as well.

Dave
On 3-Nov-05, at 9:15 PM, Neil Dugan wrote:

> Hi I am very new to Java.
>
> I am having trouble getting connection to a database.  I installed
> the Debian package 'libpg-java' version '8.0-312-1'.
>
> I can't seem to get it to work.  I copied the 'basic.java' example
> from '/usr/share/doc/libpg-java/examples/example' to the '/tmp'
> directory. Then tried to compile and run it.
> $ javac basic.java
> basic.java: In class 'example.basic':
> basic.java: In method 'example.basic.main(java.lang.String[])':
> basic.java:206: warning: The method 'setLogStream' in class
> 'java.sql.DriverManager' has been deprecated.
> DriverManager.setLogStream(System.err);
>                             ^
> 1 warning
>
> $ java basic
> java.lang.NoClassDefFoundError
>    at java.lang.VMClassLoader.nativeDefineClass (VMClassLoader.java)
>    at java.lang.VMClassLoader.defineClass (VMClassLoader.java:94)
>    at java.lang.ClassLoader.defineClass (ClassLoader.java:673)
>    at java.security.SecureClassLoader.defineClass
> (SecureClassLoader.java:108)
>    at java.net.URLClassLoader.findClass (URLClassLoader.java:926)
>    at java.lang.ClassLoader.loadClass (ClassLoader.java:360)
>    at java.lang.ClassLoader$1.loadClass (ClassLoader.java:1285)
>    at java.lang.ClassLoader.loadClass (ClassLoader.java:304)
>    at java.lang.VirtualMachine.main (VirtualMachine.java:99)
>
> Any help in getting this to work would be appreciated.
>
> Regard Neil.
>
> ---------------------------(end of
> broadcast)---------------------------
> TIP 2: Don't 'kill -9' the postmaster
>
>

Dave Cramer wrote:
> Neil,
>
> Just a shot in the dark, but I'm guessing you don't have your  classpath
> set to the current directory.
>
> ie CLASSPATH=./
>
> that will find basic
>
> then you will need to add postgresql to it as well.
>
> Dave
> On 3-Nov-05, at 9:15 PM, Neil Dugan wrote:
>
>> Hi I am very new to Java.
>>
>> I am having trouble getting connection to a database.  I installed
>> the Debian package 'libpg-java' version '8.0-312-1'.
>>
>> I can't seem to get it to work.  I copied the 'basic.java' example
>> from '/usr/share/doc/libpg-java/examples/example' to the '/tmp'
>> directory. Then tried to compile and run it.
>> $ javac basic.java
>> basic.java: In class 'example.basic':
>> basic.java: In method 'example.basic.main(java.lang.String[])':
>> basic.java:206: warning: The method 'setLogStream' in class
>> 'java.sql.DriverManager' has been deprecated.
>> DriverManager.setLogStream(System.err);
>>                             ^
>> 1 warning
>>
>> $ java basic
>> java.lang.NoClassDefFoundError
>>    at java.lang.VMClassLoader.nativeDefineClass (VMClassLoader.java)
>>    at java.lang.VMClassLoader.defineClass (VMClassLoader.java:94)
>>    at java.lang.ClassLoader.defineClass (ClassLoader.java:673)
>>    at java.security.SecureClassLoader.defineClass
>> (SecureClassLoader.java:108)
>>    at java.net.URLClassLoader.findClass (URLClassLoader.java:926)
>>    at java.lang.ClassLoader.loadClass (ClassLoader.java:360)
>>    at java.lang.ClassLoader$1.loadClass (ClassLoader.java:1285)
>>    at java.lang.ClassLoader.loadClass (ClassLoader.java:304)
>>    at java.lang.VirtualMachine.main (VirtualMachine.java:99)
>>
>> Any help in getting this to work would be appreciated.
>>
>> Regard Neil.
>>
>> ---------------------------(end of  broadcast)---------------------------
>> TIP 2: Don't 'kill -9' the postmaster
>>
>>
>
>
Thanks Dave and others,

I got the example to work.
I had to set the CLASSPATH and put the source in an 'examples' subdir.

Regards Neil.