JSP中用bean封装常用的功能

1、建立一个Bean

package guestbook;
import java.sql.*;
/**
* Title:用Javabean连接数据库
* Description:用Bean把常用的数据库功能封装，在JSP中声明该Bean。
* Copyright: Copyright (c) 2001
* Company:极速网络小组
* 编者：极速网络小组
* version 1.0
*/
public class sql_data
{
??? String sDBDriver="sun.jdbc.odbc.JdbcOdbcDriver";
??? String sConnStr="jdbc:odbc:guestbook";
??? Connection conn=null;
??? ResultSet rs=null;
??? public sql_data()
??? {
??????? try{
??????????? class.forName(sDBDriver);
??????? }
??????? catch(java.lang.ClassNotFoundException e)
??????? {
??????????? System.err.println("sql_data():"+e.getMessage());
??????? }
??? }

??? public void executeInsert(String sql)
??? {
??????? try
??????? {
??????????? conn=DriverManager.getConnection(sConnStr);
??????????? Statement stmt=conn.createStatement();
??????????? stmt.executeUpdate(sql);
??????? }
??????? catch(SQLException ex)
??????? {
??????????? System.err.println("sql_data.executeUpdate:"+ex.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("sql_data.executeQuery:"+ex.getMessage());
??????? }
??? }

??? public void executeDelete(String sql)
??? {
??????? try
??????? {
??????????? conn=DriverManager.getConnection(sConnStr);
??????????? Statement stmt=conn.createStatement();
??????????? stmt.executeUpdate(sql);
??????? }
??????? catch(SQLException ex)
??????? {
??????????? System.err.println("sql_data.executeDelete:"+ex.getMessage());
??????? }
??? }
}

2、在JSP中声明Bean：

……

<jsp:useBean id="sqlbean" scope="session" class="guestbook.sql_data"/>
<%!String sql,name;%>
<%
sql="select * from table";
ResultSet rs=sqlbean.executeQuery(sql);
while(rs.nex()){
??? name=rs.getString("name")
}
%>
……
name:<%=name%>
……
<%
rs.close();
%>
……