login.jsp
<%@ page import="java.util.Random" %>
<%@ page contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" %>
<!DOCTYPE html>
<html>
<head>
<title>登录</title>
</head>
<body>
<form action="dologin.jsp" method="post">
<p>账号：<label>
<input type="text" name="username">
</label></p>
<p>密码：<label>
<input type="password" name="password">
</label></p>
<p>验证码：<label>
<input type="number" name="verify">
</label>
<label>
<%
Random rdm = new Random();
int code1 = rdm.nextInt(100);
int code2 = rdm.nextInt(100);
%>
<input type="number" name="code1" value="<%=code1%>" hidden>
<input type="number" name="code2" value="<%=code2%>" hidden>
<%=code1%>+<%=code2%>（输入该算式的值）
</label></p>
<input type="submit" value="登录">
</form>
</body>
</html>
dologin.jsp
<%@ page import="java.sql.DriverManager" %>
<%@ page import="java.sql.Connection" %>
<%@ page import="java.sql.PreparedStatement" %>
<%@ page import="java.sql.ResultSet" %>
<%@ page contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" %>
<html>
<head>
<title>登录结果</title>
</head>
<body>
<%
String loginInfo = "";
String sign = "";
try
{
String code1 = request.getParameter("code1");
String code2 = request.getParameter("code2");
String verify = request.getParameter("verify");
int code1Int = Integer.parseInt(code1);
int code2Int = Integer.parseInt(code2);
int verifyInt = Integer.parseInt(verify);
if (code1Int + code2Int != verifyInt)
loginInfo = "登录失败，验证码不正确";
else
{
String username = request.getParameter("username");
String password = request.getParameter("password");
Class.forName("com.mysql.jdbc.Driver");
Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/user", "root", "cc461352");
PreparedStatement st = conn.prepareStatement("select upwd from usertable where uname = ?");
st.setString(1, username);
ResultSet set = st.executeQuery();
if (!set.next())
loginInfo = "用户不存在";
else
{
String pwd = set.getString(1);
if (!password.equals(pwd))
loginInfo = "登录失败，密码错误";
else
{
loginInfo = "登录成功";
sign = "hidden";
}
}
}
}
catch (Exception e)
{
e.printStackTrace();
loginInfo = "登录失败，参数错误";
}
%>
<p><%=loginInfo%></p>
<form action="index.jsp" method="get">
<input type="submit" value="返回登录" <%=sign%>>
</form>
</body>
</html>
