在JSP中用bean封装数据库常用的功能

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();

%>

……