jsp用户管理

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public String hashPassword(String password) {
    try {
        MessageDigest md = MessageDigest.getInstance("SHA-256");
        byte[] hashedBytes = md.digest(password.getBytes());
        StringBuilder sb = new StringBuilder();
        for (byte b : hashedBytes) {
            sb.append(String.format("%02x", b));
        }
        return sb.toString();
    } catch (NoSuchAlgorithmException e) {
        throw new RuntimeException("Hashing algorithm not found", e);
    }
}

HttpSession session = request.getSession();
session.setMaxInactiveInterval(30 * 60); // 设置Session超时时间为30分钟
session.invalidate(); // 销毁旧的Session
session = request.getSession(true); // 创建新的Session

String sql = "SELECT * FROM users WHERE username = ? AND password = ?";
try (PreparedStatement pstmt = connection.prepareStatement(sql)) {
    pstmt.setString(1, username);
    pstmt.setString(2, hashedPassword);
    ResultSet rs = pstmt.executeQuery();
    // 处理结果集
} catch (SQLException e) {
    e.printStackTrace();
}

<form action="registerServlet" method="post">
    Username: <input type="text" name="username"><br>
    Password: <input type="password" name="password"><br>
    <input type="submit" value="Register">
</form>

@WebServlet("/registerServlet")
public class RegisterServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String username = request.getParameter("username");
        String password = request.getParameter("password");
        String hashedPassword = hashPassword(password); // 使用上述hashPassword方法

        // 将用户名和哈希密码存入数据库
        // ...

        response.sendRedirect("login.jsp");
    }
}

<form action="loginServlet" method="post">
    Username: <input type="text" name="username"><br>
    Password: <input type="password" name="password"><br>
    <input type="submit" value="Login">
</form>

@WebServlet("/loginServlet")
public class LoginServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String username = request.getParameter("username");
        String password = request.getParameter("password");
        String hashedPassword = hashPassword(password);

        // 从数据库验证用户名和哈希密码
        // ...

        if (验证成功) {
            HttpSession session = request.getSession();
            session.setAttribute("username", username);
            response.sendRedirect("dashboard.jsp");
        } else {
            response.sendRedirect("login.jsp?error=1");
        }
    }
}