java mysql页面登录

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.sql.*;

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");

        Connection conn = null;
        PreparedStatement pstmt = null;
        ResultSet rs = null;

        try {
            // 连接数据库
            Class.forName("com.mysql.cj.jdbc.Driver");
            conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/mydatabase", "username", "password");

            // 预编译SQL语句
            String sql = "SELECT * FROM users WHERE username = ? AND password = ?";
            pstmt = conn.prepareStatement(sql);
            pstmt.setString(1, username);
            pstmt.setString(2, password);

            // 执行查询
            rs = pstmt.executeQuery();

            if (rs.next()) {
                // 登录成功，创建会话
                HttpSession session = request.getSession();
                session.setAttribute("username", username);
                response.sendRedirect("home.jsp");
            } else {
                // 登录失败
                response.sendRedirect("login.jsp?error=1");
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            // 关闭资源
            try {
                if (rs != null) rs.close();
                if (pstmt != null) pstmt.close();
                if (conn != null) conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}