在JSP中用bean封装常用的技巧

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();
%>
……

……