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Re: Dynamic classpath

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  To: comp.lang.java.gui,comp.l
Sorry, I meant Driver.connect()

Once you have loaded the driver class using a URLClassLoader, you can create a new instance and cast that to a Driver and then ask the driver to connect.

Something like this:

URLClassLoader l = new URLClassLoader(...);
Class drvClass = l.loadClass("org.postgresql.Driver");
java.sql.Driver drv = (java.sql.Driver)drvClass.newInstance();
Properties props = new Properties();
props.put("user", "postgres");
props.put("password", "password");

java.sql.Connection conn = drv.connect("jdbc:postgresql:localhost/mydb", props);

Regards
Thomas



wizard of oz, 07.05.2008 13:38:
> Can you post an example of Connection.connect (String, properties)?
> 
> My java doc says java.sql.Connection is an interface and doesn't mention a
> connect method.
> 
> TIA
> 
> "Thomas Kellerer" <YQDHXVLMUBXG@spammotel.com> wrote in message 
> news:68d9soF2r6qjbU1@mid.individual.net...
>> wizard of oz, 07.05.2008 10:41:
>>> I have a need to have a classpath that is determined by the set of 
>>> jars a user places into a directory.
>>>
>>> By way of example, placing jar's into certain directories in a tomcat 
>>> web server will cause tomcat to include them into the web 
>>> applications class path. An example of this might be a charting 
>>> package used by the web app to generate charts.
>>>
>>> In my specific example, I am building a query tool and I want to be 
>>> able to tell users to simply drop the JDBC drivers into a directory 
>>> and my app will "pick them up". Thus there would be no need to edit 
>>> the classpath.
>>>
>>> My target environment is Java 6.0
>>>
>>
>> You will need to use a URLClassLoader to load the driver(s)
>> The only problem is then doing the connection as the DriverManager 
>> will refuse to use a driver that was loaded by a different classloader.
>>
>> You have two options to resolve this:
>>
>> 1) use Connection.connect(String, Properties) directly (bypassing 
>> DriverManager) 2) create a wrapper class that pretends to be a driver 
>> but delegates everything to the real instance (loaded by your own 
>> classloader).
>> I am using option 1) without any problems.
>>
>> Thomas
>>
>

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Dynamic classpath "wizard of oz" <wizard.of.oz@THRWHITE.remove-dii-this> - 2011-04-27 15:45 +0000
  Re: Dynamic classpath "Thomas Kellerer" <thomas.kellerer@THRWHITE.remove-dii-this> - 2011-04-27 15:45 +0000
    Re: Dynamic classpath "wizard of oz" <wizard.of.oz@THRWHITE.remove-dii-this> - 2011-04-27 15:45 +0000
      Re: Dynamic classpath "Thomas Kellerer" <thomas.kellerer@THRWHITE.remove-dii-this> - 2011-04-27 15:45 +0000
  Re: Dynamic classpath "Roedy Green" <roedy.green@THRWHITE.remove-dii-this> - 2011-04-27 15:45 +0000
    Re: Dynamic classpath "Ian Shef" <ian.shef@THRWHITE.remove-dii-this> - 2011-04-27 15:45 +0000
      Re: Dynamic classpath "John B. Matthews" <john.b..matthews@THRWHITE.remove-dii-this> - 2011-04-27 15:45 +0000

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