Add a jar file to Java load path at run time

Question

Hi
I loaded my file successfully , but when I tried to use the driver to connect to the DB , I get
java.lang.ClassNotFoundException: com.ibm.db2.jcc.DB2Driver
Here is my class
import java.net.URL;
import java.io.IOException;
import java.net.URLClassLoader;
import java.net.MalformedURLException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.io.*;
public class JarFileLoader1 extends URLClassLoader
public JarFileLoader1 (URL[] urls)
super (urls);
public void addFile (String path) throws MalformedURLException
String urlPath = "jar:file://" + path + "!/";
addURL (new URL (urlPath));
public static void main (String args[])
try
File f = new File("E:\\db2_v9_5 FP5_drivers\\db2jcc.jar");
System.out.println("%%%% " + f.exists());
File f1 = new File("E:\\db2_v9_5 FP5_drivers\\db2jcc_license_cu.jar");
System.out.println("%%%% " + f1.exists());
File f2 = new File("E:\\db2_v9_5 FP5_drivers\\db2jcc4.jar");
System.out.println("%%%% " + f2.exists());
URL urls [] = {};
JarFileLoader1 cl = new JarFileLoader1 (urls);
cl.addFile ("E:\\db2_v9_5 FP5_drivers\\db2jcc.jar");
cl.addFile ("E:\\db2_v9_5 FP5_drivers\\db2jcc_license_cu.jar");
cl.addFile ("E:\\db2_v9_5 FP5_drivers\\db2jcc4.jar");
URL url = new File("E:\\db2_v9_5 FP5_drivers\\db2jcc.jar").toURL();
URLClassLoader clazzLoader = new URLClassLoader(new URL[]url);
Class clazz = clazzLoader.loadClass("com.ibm.db2.jcc.DB2Driver");
System.out.println ("Success! --> " + clazz.newInstance().toString());
String connectString = "jdbc:db2://dummy:34000/dev1";
System.out.println("BEFORE CONNECTION");
Connection conn =
DriverManager.getConnection(connectString,"mario","123123");
System.out.println("after CONNECTION");
System.out.println("Driver Version - " + conn.getMetaData().getDriverVersion() + "
catch (Exception ex)
System.out.println ("In Exception Block -- Failed.");
ex.printStackTrace (System.out);
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Here are the logging messages
%%%% true
%%%% true
%%%% true
Success! --> com.ibm.db2.jcc.DB2Driver@24442444
BEFORE CONNECTION
In Exception Block -- Failed.
java.sql.SQLException: No suitable driver
at java.sql.DriverManager.getConnection(DriverManager.java:582)
at java.sql.DriverManager.getConnection(DriverManager.java:186)
at com.tdbfg.tdsecurities.kasper.admin.aboutkasper.JarFileLoader1.main(JarFileLoader1.java:61)

Answer 1

kasper123 wrote:
Hi
I loaded my file successfully , but when I tried to use the driver to connect to the DB , I get
java.lang.ClassNotFoundException: com.ibm.db2.jcc.DB2Driver
Here is my class
import java.net.URL;
import java.io.IOException;
import java.net.URLClassLoader;
import java.net.MalformedURLException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.io.*;
public class JarFileLoader1 extends URLClassLoader
public JarFileLoader1 (URL[] urls)
super (urls);
public void addFile (String path) throws MalformedURLException
String urlPath = "jar:file://" + path + "!/";
addURL (new URL (urlPath));
public static void main (String args[])
try
File f = new File("E:\\db2_v9_5 FP5_drivers\\db2jcc.jar");
System.out.println("%%%% " + f.exists());
File f1 = new File("E:\\db2_v9_5 FP5_drivers\\db2jcc_license_cu.jar");
System.out.println("%%%% " + f1.exists());
File f2 = new File("E:\\db2_v9_5 FP5_drivers\\db2jcc4.jar");
System.out.println("%%%% " + f2.exists());
URL urls [] = {};
JarFileLoader1 cl = new JarFileLoader1 (urls);
cl.addFile ("E:\\db2_v9_5 FP5_drivers\\db2jcc.jar");
cl.addFile ("E:\\db2_v9_5 FP5_drivers\\db2jcc_license_cu.jar");
cl.addFile ("E:\\db2_v9_5 FP5_drivers\\db2jcc4.jar");
URL url = new File("E:\\db2_v9_5 FP5_drivers\\db2jcc.jar").toURL();
URLClassLoader clazzLoader = new URLClassLoader(new URL[]{url});
Class clazz = clazzLoader.loadClass("com.ibm.db2.jcc.DB2Driver");
System.out.println ("Success! --> " + clazz.newInstance().toString());
String connectString = "jdbc:db2://dummy:34000/dev1";
System.out.println("BEFORE CONNECTION");
Connection conn =
DriverManager.getConnection(connectString,"mario","123123");
System.out.println("after CONNECTION");
System.out.println("Driver Version - " + conn.getMetaData().getDriverVersion() + " ");
catch (Exception ex)
System.out.println ("In Exception Block -- Failed.");
ex.printStackTrace (System.out);
}================================================
====================================================
Here are the logging messages
%%%% true
%%%% true
%%%% true
Success! --> com.ibm.db2.jcc.DB2Driver@24442444
BEFORE CONNECTION
In Exception Block -- Failed.
java.sql.SQLException: No suitable driver
at java.sql.DriverManager.getConnection(DriverManager.java:582)
at java.sql.DriverManager.getConnection(DriverManager.java:186)
at com.tdbfg.tdsecurities.kasper.admin.aboutkasper.JarFileLoader1.main(JarFileLoader1.java:61)
For debugging purposes you could use [DriverManager.getDrivers()|http://download.oracle.com/javase/6/docs/api/java/sql/DriverManager.html#getDrivers%28%29] to get an enumeration of all drivers
and then output their names.
Maybe, with the classloader malarkey you are doing
you need to use [DriverManager.registerDriver(Driver driver)|http://download.oracle.com/javase/6/docs/api/java/sql/DriverManager.html#registerDriver%28java.sql.Driver%29]