//Opendb.Java
package Opendb;//定义opendb
import java.sql.*;//引入java.sql.*
//包中的累opendb
public class Opendb
{
    public static void main(String args[]) {
    String sDBDriver="sun.jdbc.odbc.Jdbc.OdbcDriver";
    String sConnStr="jdbc:odbc:ibm";
    Connection conn=null;
    ResultSet rs=null;
    }
    //定义打开数据库连接的函数
    public Opendb()
    {
        try
        {
            Class.forName(sDBDriver);
        }
        catch (java.lang.ClassNotFoundException e)
        {
            System.err.println("Opendb():"+e.getMessage());
        }
    }
    public ResultSet executeQuery(String sql)
    {
        rs=null;
        try
        {
            conn=DriverManager.getConnection(sConnStr);
            Statement stmt=conn.createStatement();
            rs=stmt.executeQuery(sql);
        }
        catch (SQLException ex)
        {
            System.err.println("aq.executeQuery:"+ex.getMessage());
        }
        return rs;//返回ｓｑｌ语句的执行结果
    }
}用java 编译这个的class文件提示没有找到main方法。请指教应该怎么改阿/？