ClassNotFoundException: org.gjt.mm.mysql.Driver

i have this exception this is my code
/*test1*/
String username = "root";
String password = "1234";
// The URL that will connect to TECFA’s MySQL server
// Syntax: jdbc:TYPE:machine:port/DB_NAME
String url = "jdbc:mysql://localhost:3306/contactbd";
// A canned query string
String queryString = "SELECT * FROM partenaire";
// ---- configure END
// INSTALL/load the Driver (Vendor specific Code)
try {
Class.forName("org.gjt.mm.mysql.Driver");
} catch (java.lang.ClassNotFoundException e) {
System.err.print("ClassNotFoundException: ");
System.err.println(e.getMessage());
}
try {
Connection con;
Statement stmt;
// Connection to the database at URL with usename and password
con = DriverManager.getConnection(url,username,password) ;
System.out.println ("Ok, connection to the DB worked.");
System.out.println ("Let’s see can retrieve something with: " +
queryString);
// Create a Statement Object
stmt = con.createStatement();
// Send the query and bind to the result set
ResultSet rs = (ResultSet) stmt.executeQuery(queryString);
while (rs.next()) {
String s = rs.getString("Nom");
float n = rs.getFloat("Idpar");
System.out.println(s + " " + n);
}
// Close resources
stmt.close();
con.close();
}
// print out decent error messages
catch(SQLException ex) {
System.err.println("==> SQLException: ");
while (ex != null) {
System.out.println("Message: " + ex.getMessage ());
System.out.println("SQLState: " + ex.getSQLState ());
System.out.println("ErrorCode: " + ex.getErrorCode ());
ex = ex.getNextException();
System.out.println("");
}

i am working with netbeans 7.0 i did this Class.forName("com.mysql.jdbc.Driver") but the same happend
i add the to libmysql-connector-java-5.1.18 to the Librerie of my project but the same help me please

Does that jar file contain the class you are attempting to load?
Is that jar file on the runtime classpath?

i dont have a jar file a have a zip file this mysql-connector-java-5.1.18.zip

thans i rezsolved the problem a add the jar filr