JDBC连接

Question

  package dbconn;

  import java.sql.*;

   public class DBConn {

        public static void main(String[] args) throws SQLException {
            String host = "jdbc:mysql://localhost/db_prac";
            String userName = null;
            String passCode = null;

           Connection conn = null;
           ResultSet resultSet = null;
          Statement statement = null;

        try {
           Class.forName("com.mysql.jdbc.Driver");
           conn = DriverManager.getConnection(host, userName, passCode);

        } catch(Exception e) {
           System.err.print("Error");
         }
        }
       }

我一直在尝试将jdbc与mysql连接起来，但我一直都不成功。我在运行时遇到了forName（）和getConnection（）方法的错误。我绝对空白有什么不对，哪里出错了。这是我创建问题的代码。但是当将其他程序复制并粘贴到我的IDE（Eclipse和Netbeans）时，它也会在运行时出错。Below is the image of the libraries with I've added. I am tired of searching the results on google. help is needed