js|封装|数据|数据库

在JSP中用bean封装数据库常用的功能

1、建立一个Bean

package guestbook;
import java.sql.*;


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();

%>

……