编出的代问题多多
这是一个登陆及验证界面，链接mysql数据库出问题了
ConfirmBean.java
package bean;
import java.io.*;
import java.sql.*;
public class ConfirmBean {
public Connection con=null;
public ResultSet rs=null;
private String DatabaseDriver="com.mysql.jdbc.Driver";
private String DatabaseConnStr="'jdbc:mysql://localhost/educatsystem','root','stevens'";
//定义方法
/*setXxx用于设置属性值;getXxx用于得到属性值*/
public void setDatabaseDriver(String Driver){
this.DatabaseDriver=Driver;
}
public String getDatabaseDriver(){
return (this.DatabaseDriver);
}
public void setDatabaseConnStr(String ConnStr){
this.DatabaseConnStr=ConnStr;
}
public String getDatabaseConnStr(){
return (this.DatabaseConnStr);
}
public ConfirmBean(){//构造函数
try{
Class.forName(DatabaseDriver);
}
catch(java.lang.ClassNotFoundException e){
System.err.println("加载驱动器有错误:"+e.getMessage( ));
System.out.print("执行插入有错误:"+e.getMessage());//输出到客户端
}
}
public String getString(String name) throws SQLException{
if(rs==null) throw new SQLException("ResultSet is null");
return String.valueOf(rs.getString(name));
}
public void executeInsert(String sql){
try{
con = DriverManager.getConnection("jdbc:mysql://localhost/educatsystem","root","stevens");
Statement stmt=con.createStatement( );
stmt.executeUpdate(sql);
}
catch(SQLException ex){
System.err.println("执行插入有错误:"+ex.getMessage() );
System.out.print("执行插入有错误:"+ex.getMessage());//输出到客户端
}
}
// display data
public ResultSet executeQuery(String sql){
rs=null;
try{
con = DriverManager.getConnection("jdbc:mysql://localhost/educatsystem","root","stevens");
Statement stmt=con.createStatement( );
rs=stmt.executeQuery(sql);
}
catch(SQLException ex){
System.err.println("执行查询有错误:"+ex.getMessage() );
System.out.print("执行查询有错误:"+ex.getMessage()); //输出到客户端
}
return rs;
}
// delete data
public void executeDelete(String sql){
try{
con = DriverManager.getConnection("jdbc:mysql://localhost/educatsystem","root","stevens");
Statement stmt=con.createStatement( );
stmt.executeUpdate(sql);
}
catch(SQLException ex){
System.err.println("执行删除有错误:"+ex.getMessage() );
System.out.print("执行删除有错误:"+ex.getMessage()); //输出到客户端
}
}
public void CloseDataBase(){
try{
con.close();
}
catch(Exception end){
System.err.println("执行关闭Connection对象有错误："+end.getMessage( ) );
System.out.print("执行执行关闭Connection对象有错误：有错误:"+end.getMessage()); //输出到客户端
}
}
}
<%@ page language="java" import="java.util.*" pageEncoding="gb2312"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<html>
<head>
<base href="<%=basePath%>">
<title>登陆</title>
<style type="text/css">
body {
background-color: #9C3;
}
</style>
</head>
<body>
<jsp:include page="head.jsp"></jsp:include><br/>
<p><font color="blue" size=6>欢迎您登陆教师管理系统</font></p><br/>
<form action="login_confirm.jsp" name="formlogin" method="post">
登录名:<input type="text" name="name"><br/><br/>
密 码:<input type="password" name="password"><br/><br/>
<input type="submit" name="submit" value="登陆">
</form>
</body>
</html>
<%@ page language="java" import="java.util.*" pageEncoding="gb2312"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<html>
<head>
<base href="<%=basePath%>">
<title>登陆检验</title>
</head>
<body>
<jsp:useBean id="db" class="bean.ConfirmBean"> </jsp:useBean>
<%
response.setContentType("text/html;charset=gb2312");
request.setCharacterEncoding("gb2312");
String name=request.getParameter("logname");
if(name==null)
{name="";
}
byte b[]=name.getBytes("gb2312");
name=new String(b);
String password=request.getParameter("password");
if(password==null)
{password="";
}
byte c[]=name.getBytes("gb2312");
name=new String(c);
%>
<%
String sql="INSERT INTO registmessage VALUES"+"("+"'"+name+"','"+password+")";
db.getDatabaseConnStr();
db.setDatabaseConnStr("'jdbc:mysql://localhost/educatsystem','root','stevens'");
db.getDatabaseDriver();
db.setDatabaseDriver("com.mysql.jdbc.Driver");
db.executeInsert("sql");
db.executeQuery("sql");
%>
</body>
</html>
ConfirmBean.java
package bean; import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; public class ConfirmBean { public boolean testLogin(String name, String password) { Connection con = null; Statement stmt = null; ResultSet rs = null; boolean flag = false; String sql = "SELECT * FROM registmessage WHERE name = '" + name + "'" + " AND password='" + password + "'"; try { Class.forName("com.mysql.jdbc.Driver"); con = DriverManager.getConnection("jdbc:mysql://localhost/educatsystem", "root", "stevens"); } catch (Exception e) { System.err.println("数据库连接加载异常:" + e.getMessage()); e.printStackTrace(); } try { stmt = con.createStatement(); rs = stmt.executeQuery(sql); if (rs.next()) { // 查询结果有数据 flag = true; } } catch (SQLException ex) { System.err.println("执行查询有错误:" + ex.getMessage()); System.out.print("执行查询有错误:" + ex.getMessage()); // 输出到客户端 } finally { try { stmt.close(); rs.close(); con.close(); } catch (SQLException e) { e.printStackTrace(); } } return flag; } }login_confirm.jsp
<%@ page language="java" pageEncoding="gb2312"%> <%@page import="bean.ConfirmBean"%> <% String path = request.getContextPath(); String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort() + path + "/"; %> <html> <head> <base href="<%=basePath%>"> <title>登陆检验</title> </head> <body> <% response.setContentType("text/html;charset=gb2312"); request.setCharacterEncoding("gb2312"); String name = request.getParameter("logname"); String password = request.getParameter("password"); if (name == null) { name = ""; out.println("用户名为空"); } if (password == null) { password = ""; out.println("密码为空"); } boolean flag = new ConfirmBean().testLogin(name,password); if(flag){ out.println("登陆成功"); }else{ out.println("登陆失败"); } %> </body> </html>没测试，可以试试~！~错误是什么？
另外，db.executeQuery("sql"); 很雷人
这两个不用加引号，但是你sql是插入语句调用executeQuery没有意义
<jsp:useBean id="db" class="bean.ConfirmBean"> //需要跳转前传递过来，要不就是null了，后面都会报错 //例如： request.setAttribute("db",new bean.ConfirmBean());