使用JSP+Servlet+JDBC技术 三层架构 对atm库中的atm_user表进行 1，登录 2，列表（user_name条件模糊查询） 3，删除

好的，我可以为您提供一个简单的示例代码。 首先，我们需要建立一个三层架构的项目，包含 DAO 层、Service 层和 Controller 层。 在 DAO 层中，我们可以定义一个 UserDao 接口和一个 UserDaoImpl 类来实现该接口。在 UserDao 接口中，我们可以定义登录、列表和删除等操作的方法。在 UserDaoImpl 类中，我们可以使用 JDBC 技术来实现这些方法。 在 Service 层中，我们可以定义一个 UserService 接口和一个 UserServiceImpl 类来实现该接口。在 UserServiceImpl 类中，我们可以调用 UserDaoImpl 中的方法，并对数据进行一些处理和封装。 在 Controller 层中，我们可以定义一个 UserServlet 类来处理用户请求。在 UserServlet 类中，我们可以调用 UserServiceImpl 中的方法，并将结果发送给用户界面。 下面是示例代码： UserDao.java ```java public interface UserDao { boolean login(String username, String password) throws SQLException; List<User> getUserList(String username) throws SQLException; boolean deleteUser(int id) throws SQLException; } ``` UserDaoImpl.java ```java public class UserDaoImpl implements UserDao { private Connection conn = null; private PreparedStatement pstmt = null; public UserDaoImpl(Connection conn) { this.conn = conn; } @Override public boolean login(String username, String password) throws SQLException { String sql = "SELECT * FROM atm_user WHERE user_name=? AND user_password=?"; pstmt = conn.prepareStatement(sql); pstmt.setString(1, username); pstmt.setString(2, password); ResultSet rs = pstmt.executeQuery(); if (rs.next()) { return true; } else { return false; } } @Override public List<User> getUserList(String username) throws SQLException { List<User> userList = new ArrayList<>(); String sql = "SELECT * FROM atm_user WHERE user_name LIKE ?"; pstmt = conn.prepareStatement(sql); pstmt.setString(1, "%" + username + "%"); ResultSet rs = pstmt.executeQuery(); while (rs.next()) { User user = new User(); user.setId(rs.getInt("user_id")); user.setUsername(rs.getString("user_name")); user.setPassword(rs.getString("user_password")); user.setBalance(rs.getDouble("user_balance")); userList.add(user); } return userList; } @Override public boolean deleteUser(int id) throws SQLException { String sql = "DELETE FROM atm_user WHERE user_id=?"; pstmt = conn.prepareStatement(sql); pstmt.setInt(1, id); int result = pstmt.executeUpdate(); if (result > 0) { return true; } else { return false; } } } ``` UserService.java ```java public interface UserService { boolean login(String username, String password) throws SQLException; List<User> getUserList(String username) throws SQLException; boolean deleteUser(int id) throws SQLException; } ``` UserServiceImpl.java ```java public class UserServiceImpl implements UserService { private UserDao userDao; public UserServiceImpl(UserDao userDao) { this.userDao = userDao; } @Override public boolean login(String username, String password) throws SQLException { return userDao.login(username, password); } @Override public List<User> getUserList(String username) throws SQLException { return userDao.getUserList(username); } @Override public boolean deleteUser(int id) throws SQLException { return userDao.deleteUser(id); } } ``` UserServlet.java ```java public class UserServlet extends HttpServlet { private UserService userService; public UserServlet() { super(); userDao = new UserDaoImpl(DBUtil.getConnection()); userService = new UserServiceImpl(userDao); } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doPost(request, response); } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String action = request.getParameter("action"); if (action.equals("login")) { String username = request.getParameter("username"); String password = request.getParameter("password"); try { if (userService.login(username, password)) { response.sendRedirect("userList.jsp"); } else { response.sendRedirect("login.jsp"); } } catch (SQLException e) { e.printStackTrace(); } } else if (action.equals("list")) { String username = request.getParameter("username"); try { List<User> userList = userService.getUserList(username); request.setAttribute("userList", userList); RequestDispatcher rd = request.getRequestDispatcher("userList.jsp"); rd.forward(request, response); } catch (SQLException e) { e.printStackTrace(); } } else if (action.equals("delete")) { int id = Integer.parseInt(request.getParameter("id")); try { userService.deleteUser(id); response.sendRedirect("userList.jsp"); } catch (SQLException e) { e.printStackTrace(); } } } } ``` 以上代码仅供参考，具体的实现还需要您根据自己的需求进行修改。希望对您有所帮助！