Cannot connect to test database in java with jdbc

jtiernan

I got this off the link below
http://www.stardeveloper.com/articles/display.html?article=2003090201&page=4

I have set CLASSPATH to C:\Program Files\Java\jre1.6.0_03\lib\ext\'mysql-connector-java-5.1.5-bin.jar

I am using Jcreator IDE



package com.stardeveloper.example;

import java.sql.*;

public class JdbcExample1 {

public static void main(String args[]) {
Connection con = null;

try {
Class.forName("com.mysql.jdbc.Driver").newInstance();
con = DriverManager.getConnection("jdbc:mysql:///test", "root", "secret");

if(!con.isClosed())
System.out.println("Successfully connected to MySQL server...");

}
catch(Exception e) {
e.printStackTrace();
}
finally {
try {
if(con != null)
con.close();
} catch(SQLException e) {}
}
}
}

It compiles fine but gives the exception below;

---

Configuration: <Default>

---

java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:276)
at java.lang.ClassLoader.loadClass(ClassLoader.java:251)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:169)
at com.stardeveloper.example.JdbcExample1.main(JdbcExample1.java:11)

Process completed.

Please help:(

smcelhinney

Its definitely a classpath error. How are you running the program? Have you tried a command line compile and run??

I've never used JCreator, only eclipse and netbeans, but this is definitely because the runtime processor cannot find the required library (the Connector/J one).

brian_rbk

have you tried copying the mysql-connector-java-3.0.17-ga-bin.jar file into the lib folder of your project. I'm using netbeans, and it worked as soon as i did that.

marco_polo

jtiernan wrote: »

I got this off the link below
http://www.stardeveloper.com/articles/display.html?article=2003090201&page=4

I have set CLASSPATH to C:\Program Files\Java\jre1.6.0_03\lib\ext\'mysql-connector-java-5.1.5-bin.jar

I am using Jcreator IDE



package com.stardeveloper.example;

import java.sql.*;

public class JdbcExample1 {

public static void main(String args[]) {
Connection con = null;

try {
Class.forName("com.mysql.jdbc.Driver").newInstance();
con = DriverManager.getConnection("jdbc:mysql:///test", "root", "secret");

if(!con.isClosed())
System.out.println("Successfully connected to MySQL server...");

}
catch(Exception e) {
e.printStackTrace();
}
finally {
try {
if(con != null)
con.close();
} catch(SQLException e) {}
}
}
}

It compiles fine but gives the exception below;

---

Configuration: <Default>

---

java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:276)
at java.lang.ClassLoader.loadClass(ClassLoader.java:251)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:169)
at com.stardeveloper.example.JdbcExample1.main(JdbcExample1.java:11)

Process completed.

Please help:(

I am coming from Eclipse here so and I haven't used JCreator myself.

I take it you are using the JCreator IDE to compile and run the program rather than the command line? If so, more than likely it doesn't use the system classpath when it is compilling and running programs, but probably has it own internal classpath somewhere..

If you have a look around in the menu for Properties or settings, I am sure you will find something like Classpath / Build Path. If you add the jar in here it should work just fine.