RT:
<%@ page language="java" import="java.util.*" pageEncoding="gb2312"%>
<%@ page import="java.sql.*" %>
<%@page import="pc.DBHelper"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>My JSP 'newsList.jsp' starting page</title>
</head>
<jsp:useBean id="Conn" class="pc.DBHelper"/>
<body>
<table width="200" cellspacing="1" cellpadding="1">
<tr>
<td>ID</td>
<td>名称</td>
</tr>
<% ResultSet rs1 = Conn.getResultSet("select * from news quot"); %>
<% while(rs1.next())
{%>
<tr>
<td><%= rs1.getInt("id")%></td>
<td><%= rs1.getString("content")%></td>
</tr>
<%} %>
</table>
</body>
</html>
页面
package pc;
import java.sql.*;
public class DBHelper
{
static final String DriverName="com.mysql.jdbc.Driver"; //driver
static final String dbURL="jdbc:mysql://localhost/test?useUnicode=true&characterEncoding=GBK";
public static Connection getConnection()
{
Connection conn = null;
try
{
Class.forName(DriverName);
conn = DriverManager.getConnection(dbURL,"root","root"); //conn object
}
catch (Exception e){}
return conn;
}
public static void Close(Connection conn)
{
try //conn close
{
if(conn!=null)
conn.close();
}
catch(Exception e){}
}
public void Close(ResultSet rs) //resultset close
{
try
{
if(rs!=null)
rs.close();
}
catch(Exception e){}
}
public void Close(Statement operation) //statement close
{
try
{
if(operation!=null)
operation.close();
}
catch(Exception e){}
}
public ResultSet getResultSet(String st)
{
try
{
Statement operation1 = DBHelper.getConnection().createStatement();
ResultSet rs1 = operation1.executeQuery(st);
return rs1;
}
catch (Exception e)
{}
return null;
}
public int getexecuteUpdate(String st)
{
int i = -1;
try
{
Statement stmt = (DBHelper.getConnection()).createStatement();
i = stmt.executeUpdate(st);
return i;
}
catch (Exception e)
{e.printStackTrace();}
return i;
}
}
.java
为什么 rs.next()报错？
------解决方案--------------------
- Java code
public final class JdbcUtilsSing { private String url = "jdbc:mysql://localhost:3306/jdbc"; private String user = "root"; private String password = ""; // private static JdbcUtilsSing instance = new JdbcUtilsSing(); private static JdbcUtilsSing instance = null; private JdbcUtilsSing() { } public static JdbcUtilsSing getInstance() { if (instance == null) { synchronized (JdbcUtilsSing.class) { if (instance == null) { instance = new JdbcUtilsSing(); } } } return instance; } static { try { Class.forName("com.mysql.jdbc.Driver"); } catch (ClassNotFoundException e) { throw new ExceptionInInitializerError(e); } } public Connection getConnection() throws SQLException { return DriverManager.getConnection(url, user, password); } public void free(ResultSet rs, Statement st, Connection conn) { try { if (rs != null) rs.close(); } catch (SQLException e) { e.printStackTrace(); } finally { try { if (st != null) st.close(); } catch (SQLException e) { e.printStackTrace(); } finally { if (conn != null) try { conn.close(); } catch (SQLException e) { e.printStackTrace(); } } } }}