Tomcat 配置的数据源，测试连接数据库报告类转换错误。

tomcat 配置的数据源如下： auth="Container"
type="javax.sql.DataSource"
maxActive="100" maxIdle="30" maxWait="10000"
username="root" password="root" driverClassName="com.mysql.jdbc.Driver"
url="jdbc:mysql://localhost:3306/mydb" />

写的测试类如下：
package com.telenav.Brant;

import java.sql.ResultSet;
import java.sql.SQLException;

import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.sql.DataSource;

import com.mysql.jdbc.Connection;
import com.mysql.jdbc.Statement;

public class ConnectDB {
public ConnectDB(){}

public static void testDB(){
try {
Context ctx = new InitialContext();
DataSource ds = (DataSource) ctx.lookup("java:comp/env/jdbc/TestDB");
Connection con = (Connection) ds.getConnection();
Statement stmt = (Statement) con.createStatement();
ResultSet rs = stmt.executeQuery("select * from user");
while(rs.next()){
System.out.println(rs.getString(2));
}
} catch (NamingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
报错如下：
2011-6-19 15:08:28 org.apache.catalina.core.StandardWrapperValve invoke
严重: Servlet.service() for servlet jsp threw exception
java.lang.ClassCastException: org.apache.tomcat.dbcp.dbcp.PoolingDataSource$PoolGuardConnectionWrapper cannot be cast to com.mysql.jdbc.Connection
at com.telenav.Brant.ConnectDB.testDB(ConnectDB.java:21)
at org.apache.jsp.index_jsp._jspService(index_jsp.java:81)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.jasper.servlet.JspServletWrapper.service

我估计是import进来的类不对，可能是引入的包比较少，所以eclipse自动提示的类不匹配，有没有高手告诉我使用tomcat数据源配置连接数据库，在类中都要引入什么包中的什么类？