MySQL jdbc driver and Eclipse: ClassNotFoundexception com.mysql.jdbc.Driver

Question

There is a VERY similar question to mine but in my case I don't have any duplicate jars in my build path, so the solution does not work for me. I've searched google for a couple of hours now, but none of the solutions I've found there actually resolve my issue. I'm creating a web site with some database connectivity for a homework. I'm using a MySQL database, developing in Eclipse and running on Windows.

I keep getting java.lang.ClassNotFoundException: com.mysql.jdbc.Driver with the following code:

import java.sql.*;
//...
public void someMethodInMyServlet(PrintWriter out)
{
    Connection connection = null;
    PreparedStatement query = null;
    try {

        out.println("Create the driver instance.<br>");
        Class.forName("com.mysql.jdbc.Driver").newInstance();

        out.println("Get the connection.<br>");
        connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "secret");
        query = connection.prepareStatement( "SELECT * FROM customers");

        //...
    } catch (Exception e)
    {
        out.println(e.toString()+"<br>");
    }
}
//...

When I run the above code I get the following output:

Create the driver instance.
java.lang.ClassNotFoundException: com.mysql.jdbc.Driver

It doesn't get past the Class.forName... line and I can't figure out why! Here is what I did:

1. Download mysql-connector.
2. Put it in my MySQL folder C:\Program Files\MySQL\mysql-connector-java-5.1.12\mysql-connector-java-5.1.12-bin.jar.
3. Opened the project properties in Eclipse.
4. Add External Jar to my Build Path and I selected mysql-connector-java-5.1.12-bin.jar.

Every time I attempt to use the servlet I get the same error regardless if I have the jar in there or if I don't. Could you help me figure this out?

Answer 1

Since you are running it in servlet, you need to have the jar accessible by the servlet container. You either include the connector as part of your application war or put it as part of the servlet container's extended library and datasource management stuff, if it has one. The second part is totally depend on the container that you have.

Answer 2

As for every "3rd-party" library in flavor of a JAR file which is to be used by the webapp, just copy/drop it in webapp's /WEB-INF/lib. It will then be available in webapp's default classpath. Also, Eclipse is smart enough to notice that. No need to hassle with buildpath. However, make sure to remove all unnecessary references you added before, else it might collide.

Answer 3

The others are right about making the driver JAR available to your servlet container. My comment was meant to suggest that you verify from the command line whether the driver itself is intact.

Rather than an empty main(), try something like this, adapted from the included documentation:

public class LoadDriver {
    public static void main(String[] args) throws Exception {
        Class.forName("com.mysql.jdbc.Driver");
    }
}

On my platform, I'd do this:

$ ls mysql-connector-java-5.1.12-bin.jar 
mysql-connector-java-5.1.12-bin.jar
$ javac LoadDriver.java 
$ java -cp mysql-connector-java-5.1.12-bin.jar:. LoadDriver

On your platform, you need to use ; as the path separator, as discussed here and here.