写了一个数据库访问的bean如下:package todb;import java.sql.*;import java.io.*;public class  DBBean implements Serializable{  private String DBDriver = "com.microsoft.jdbc.sqlserver.SQLServerDriver";  private String DBLocation = "jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=bbs";  private String LogName = "hamduke";  private String Password= "2682226";  Connection conn = null;  ResultSet  rs = null;  Statement  stmt = null;  String strHint = "";  public void DBBean() {  }  public void setDBDriver(String driver){ DBDriver = driver;}  public String getDBDriver(){ return DBDriver; }  public void setDBLocation(String location){ DBLocation = location;}  public String getDBLocation(){ return DBLocation; }  public void setLogName(String logname){ LogName = logname;}  public void setPassword(String password){ Password = password;}  public String getHint(){return strHint;}  public void initBean(){    try { Class.forName(DBDriver); }    catch(java.lang.ClassNotFoundException e) {                System.err.println("initBean(): " + e.getMessage());        }  }  public Connection getConn(){    try { conn = DriverManager.getConnection(DBLocation,LogName,Password); }        catch(SQLException ex) {          System.err.println("getConn(): " + ex.getMessage());                  }    return conn;   }//~getConn  public ResultSet executeQuery(String sql){    rs = null;    try{                 conn = getConn();         stmt = conn.createStatement();         rs = stmt.executeQuery(sql);        }     catch(SQLException ex)        {          strHint = "executeQuery: " + ex.getMessage();                  System.err.println(strHint);        }        return rs;    }        //execute a SQL statement without returning recordset    public boolean executeUpdate(String sql)    {        try        {                conn = getConn();            stmt = conn.createStatement();            stmt.executeUpdate(sql);            return true;        }        catch(SQLException ex)        {                strHint = "executeUpdate: " + ex.getMessage();                        System.err.println(strHint);            return false;        }    }        //Close connections    public boolean closeConn()    {                   try        {                           if (rs!=null)                    rs.close();                           if (stmt!=null)                    stmt.close();                    if (conn!=null)                    conn.close();            return true;            }        catch(SQLException ex)        {                        strHint = "closeConn: " + ex.getMessage();                        System.err.println(strHint);            return false;        }    }