日期:2014-05-17  浏览次数:20662 次

请教jsp连接mysql的问题.
mysqlrs.java
Java code
package anhua;
import java.sql.*;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

public class mysqlrs {
    Connection con = null; 
    Statement stat = null; 
    PreparedStatement pstat = null;
    ResultSet rs = null;

    //无参数的构造函数 
    public mysqlrs(){}
    //取得数据库连接 
    public Connection getCon()
    { 
    try{   
    Class.forName("com.mysql.jdbc.Driver").newInstance();   
    String url = "jdbc:mysql://localhost:3306/anhua?user=root&password=123456&useUnicode=true&characterEncoding=utf-8";   
    con = DriverManager.getConnection(url); 
    }
    catch(Exception ex)
    {   
        //ex.printStackTrace(); 
        //System.err.print("Exception");
        //out.print( "yes ");
    } 
    return con;   
    }

    //执行数据库查询并返回查询结果

    public ResultSet query(String sql)
    { 
    try{   con = getCon();   
    stat = con.createStatement();   
    rs = stat.executeQuery(sql); 
    }
    catch(Exception ex)
    {   
    //ex.printStackTrace(); 
    System.err.print("SQLException");
    } 
    return rs; 
    }

    //执行数据库更新 
    public void update(String sql)
    { 
    try{   
    con = getCon();   
    stat = con.createStatement();   
    stat.executeUpdate(sql); 
    }
    catch(Exception ex)
    {   
    ex.printStackTrace(); 
    } 
    }

    //执行数据库更新 
    public void update(String sql,String[] args)
    { 
    try{   
    con = getCon(); 
    pstat = con.prepareStatement(sql); 
    for (int i=0;i<args.length;i++)
    {    
    pstat.setString(i+1,args[i]); 
    }   
    pstat.executeUpdate(); 
    }
    catch(Exception ex)
    {   
    ex.printStackTrace(); 
    } 
    }

    //关闭数据库连接
    public void close()
    { 
    try{ 
    if (rs != null)rs.close(); 
    if (stat != null)stat.close();   
    if (pstat != null)pstat.close();   
    if (con != null)con.close(); }
    catch(Exception ex)
    {   
    ex.printStackTrace(); 
    } 
    } 
}


index.jsp
Java code
<%@ page contentType="text/html; charset=utf-8" language="java" import="java.sql.*" errorPage="" %>
<%@ page import="java.io.*" %>
<jsp:useBean id="myDBbean" class="anhua.mysqlrs"></jsp:useBean>
<%!
private static int Num;
public void japInit(){
    Num=0;
    };
%>
<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
</head>

<body>
<%="<br />欢迎<br />"%>
<% Num++; %>
<%="您是第"+Num+"个客人"%>
<Table border=2 bordercolor="#FFCCCC" align="center">
<tr bgcolor=CCCCCC align=center>
    
    <td><b>书号</b></td>
    <td><b>书名</b></td>
    <td><b>作者</b></td>
    <td><b>出版社</b></td>
    <td><b>出版社</b></td>
    <td><b>出版社</b></td>
    
</tr>
<%
ResultSet rs = myDBbean.query("select * from users");
   while(rs.next()){
%>   
   <tr align=center>
    
    <td><%=rs.getString("id")%></td> 
    <td><%=rs.getString("uname")%></td>
    <td><%=rs.getString("upass")%><