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下一篇：利用JSP+JDBC实现网站的留言功能
创建用户表，能完成用户登录验证和用户注册功能。
实现如下效果：
主要代码如下：完整版可在github下载完整代码期待你的小星星
login.jsp
<%@ page contentType="text/html; charset=gb2312" language="java" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>starting page</title>
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
<style type="text/css">
<!--
.STYLE2 {
font-family: "Courier New", Courier, monospace;
font-size: 16px;
font-weight: bold;
color: red;
}
-->
</style>
</head>
<body>
<p align="center" class="STYLE2"> 用户登录页面</p>
<%
if(request.getAttribute("error") != null){
%>
<center>
<h3> <font color="red" ><%=request.getAttribute("error") %></font></h3>
</center>
<% }
%>
<%String info=request.getParameter("info");
if(info==null)info="";%>
<font color=red><%=info %></font>
<form id="form1" name="form1" method="post" action="suess.jsp">
<table width="337" height="124" border="1" align="center">
<tr>
<td width="77">用户名：</td>
<td width="107"><label>
<input name="username" type="text" id="id" size="20" maxlength="20" />
</label></td>
</tr>
<tr>
<td>密 码：</td>
<td><label>
<input name="password" type="password" id="password" size="20" maxlength="20" />
</label></td>
</tr>
<tr>
<td><label>
<input type="submit" name="submit" id="submit" value="登录" />
</label></td>
<td><label>
<input type="reset" name="reset" id="reset" value="重置" />
</label></td>
</tr>
</table>
</form>
<a href=register.jsp>注册用户</a>
</body>
</html>
login_conf.jsp
<%@ page language="java" contentType="text/html; charset=gb2312"
pageEncoding="gb2312" import="java.sql.*"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>Insert title here</title>
</head>
<body>
<%
String username = request.getParameter("username") ;
String password = request.getParameter("userPassword") ;
final String DBDRRIVER = "com.mysql.jdbc.Driver" ;
final String DBURL = "jdbc:mysql://localhost:3306/test2";
final String DBUSERNAME = "root" ;
final String DBPASSWORD = "123" ;
Connection conn = null ;
PreparedStatement pstmt = null ;
String sql = null ;
if(username!=null&&password!=null){
try{
Class.forName(DBDRRIVER) ;
conn = DriverManager.getConnection(DBURL,DBUSERNAME,DBPASSWORD) ;
sql = "insert into users (username,userpassword) values (?,?)" ;
pstmt = conn.prepareStatement(sql) ;
pstmt.setString(1,username) ;
pstmt.setString(2,password) ;
pstmt.executeUpdate() ;
pstmt.close() ;
conn.close() ;
%>
<h3>注册成功!!!</h3>
<h3>三秒钟后自动转到登录页面!!!</h3>
<h3>如果没有跳转，请点击<a href="login.jsp">这里</a>!!!</h3>
<%
response.setHeader("refresh","3;url=login.jsp") ;
}catch(Exception e){
%>
<h3>注册失败!!!</h3>
<h3><%=e%></h3>
<%
}
}
%>
</body>
</html>
register.jsp
<%@ page contentType="text/html; charset=gb2312" language="java" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>新用户注册</title>
<script language="javascript">
//判断输入的用户名和密码是否合法
function check()
{
if(reg_form.username.value == "")
{//判断用户名是否为空
alert("用户名不能为空！");
reg_form.userName.focus();
}
else if(reg_form.userPassword.value == "")
{//判断密码是否为空
alert("用户密码不能为空！");
reg_form.userPassword.focus();
}
else if(reg_form.userPassword.value != reg_form.confirm_UserPassword.value)
{//判断两次输入的密码是否一致
alert("两次输入的密码不一致！");
reg_form.userPassword.focus();
}
else
{
//设置跳转目的页面
reg_form.action="login_conf.jsp";
}
}
</script>
</head>
<body>
<p align="center"><font size="5">新用户注册</font></p>
<div align="center">
<form name="reg_form" method="post" onSubmit="check()">
<table width="60%" border="0">
<tr>
<td width="50%" align="right">请输入用户名：</td>
<td width="50%" align="left"><input type="text" name="username"></td>
</tr>
<tr>
<td width="50%" align="right">请输入密码：</td>
<td width="50%" align="left"><input type="password" name="userPassword"></td>
</tr>
<tr>
<td width="50%" align="right">请输入确认密码：</td>
<td width="50%" align="left"><input type="password" name="confirm_UserPassword"></td>
</tr>
<tr>
<td width="50%" align="center" colspan="2">
<br>
<input type="submit" name="sub" value="注册">
<input type="reset" name="res" value="重填">
</td>
</tr>
</table>
</form>
</div>
</body>
</html>
sucess.jsp
<%@ page contentType="text/html; charset=gb2312" language="java" import="java.sql.*"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>登录成功</title>
</head>
<body>
<%
String username = request.getParameter("username") ;
String password = request.getParameter("password") ;
final String DBDRRIVER = "com.mysql.jdbc.Driver" ;
final String DBURL = "jdbc:mysql://localhost:3306/test2" ;
final String DBUSERNAME = "root" ;
final String DBPASSWORD = "123" ;
Connection conn = null ;
PreparedStatement pstmt = null ;
String sql = null ;
out.print(username);
if(username!=null&&password!=null){
try{
Class.forName(DBDRRIVER) ;
conn = DriverManager.getConnection(DBURL,DBUSERNAME,DBPASSWORD) ;
sql = "select * from users where username=? and userpassword=?;" ;
pstmt = conn.prepareStatement(sql) ;
pstmt.setString(1,username) ;
pstmt.setString(2,password) ;
ResultSet aa=pstmt.executeQuery();
if(!aa.next())response.sendRedirect("login.jsp?please login again!");
else out.println("登录成功");
pstmt.close() ;
conn.close() ;
}catch(Exception e){
%>
<h3>登录失败!!!</h3>
<h3><%=e%></h3>
<%
}
}
%>
</body>
</html>
效果截图：
以上仅是主要代码部分，如需要完整项目，可在GitHub上面下载，完整项目代码地址
