利用javaBean操作数据库表及其子段

我在大三的时候写过一个javabean，可以实现连接数据库，对表的操作，以及对其中的字段值经过字符串运算后提取新的SQL条件，我现在拿出来与大家共享。

dbBean.java//连接数据库SQL Server2000

package pub;
import java.sql.*;
import java.io.*;
import java.util.*;
 
public class dbBean {
 
 public Connection conn = null;
 public Statement stmt = null;
 public ResultSet rs = null;

 public dbBean() {
  try {
 Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
      }
  catch (ClassNotFoundException e) {
        System.err.println("OpenDB():"+e.getMessage());
                                  }
                 }
 public ResultSet executeQuery(String sql) {
  try {
 conn=DriverManager.getConnection("jdbc:odbc:KMHXBY","sa","");
 stmt=conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);
        rs = stmt.executeQuery(sql);//execute sql
      }
  catch (java.sql.SQLException e) {
        System.err.println("OpenDB.executeQuery():"+e.getMessage());
                                  }
        return rs;
                                           }
 public int executeUpdate(String sql) {
  int rowscount=0;
  try {
 conn=DriverManager.getConnection("jdbc:odbc:foxv21","sa","");
 stmt=conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);
        rowscount = stmt.executeUpdate(sql);//execute sql
      }
  catch (java.sql.SQLException e) {
        System.err.println("OpenDB.executeUpdate():"+e.getMessage());
        }
        return rowscount;
           }
 public void destroy() {
  try {
 stmt.close();
        conn.close();
      }
  catch(Exception e) {
        System.err.println("DBOperate.destroy():"+e.getMessage());