jsp+servlet+javabean+jdbc实现数据库的登录注册验证代码

好的，以下是一个简单的代码示例（仅供参考）：

1. 创建数据库表

CREATE TABLE `user` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `username` varchar(50) NOT NULL,
  `password` varchar(50) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

2. 编写 JavaBean

User.java

public class User {
    private int id;
    private String username;
    private String password;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }
}

3. 编写 DAO 类

UserDao.java

public class UserDao {
    // 数据库连接信息
    private String url = "jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf-8";
    private String username = "root";
    private String password = "root";

    // 注册用户
    public boolean register(User user) {
        Connection conn = null;
        PreparedStatement stmt = null;
        try {
            // 获取数据库连接
            conn = DriverManager.getConnection(url, username, password);
            // 编写 SQL 语句
            String sql = "INSERT INTO user(username, password) VALUES(?, ?)";
            // 创建 PreparedStatement 对象
            stmt = conn.prepareStatement(sql);
            // 设置参数
            stmt.setString(1, user.getUsername());
            stmt.setString(2, user.getPassword());
            // 执行 SQL
            int result = stmt.executeUpdate();
            // 处理结果
            return result > 0;
        } catch (SQLException e) {
            e.printStackTrace();
            return false;
        } finally {
            // 关闭资源
            try {
                if (stmt != null) {
                    stmt.close();
                }
                if (conn != null) {
                    conn.close();
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

    // 验证用户信息
    public boolean login(User user) {
        Connection conn = null;
        PreparedStatement stmt = null;
        ResultSet rs = null;
        try {
            // 获取数据库连接
            conn = DriverManager.getConnection(url, username, password);
            // 编写 SQL 语句
            String sql = "SELECT * FROM user WHERE username=? AND password=?";
            // 创建 PreparedStatement 对象
            stmt = conn.prepareStatement(sql);
            // 设置参数
            stmt.setString(1, user.getUsername());
            stmt.setString(2, user.getPassword());
            // 执行 SQL
            rs = stmt.executeQuery();
            // 处理结果
            return rs.next();
        } catch (SQLException e) {
            e.printStackTrace();
            return false;
        } finally {
            // 关闭资源
            try {
                if (rs != null) {
                    rs.close();
                }
                if (stmt != null) {
                    stmt.close();
                }
                if (conn != null) {
                    conn.close();
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}

4. 编写 Servlet

UserServlet.java

public class UserServlet extends HttpServlet {
    private UserDao userDao = new UserDao();

    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        // 设置请求编码和响应编码
        request.setCharacterEncoding("UTF-8");
        response.setContentType("text/html;charset=UTF-8");

        // 获取请求参数
        String action = request.getParameter("action");
        String username = request.getParameter("username");
        String password = request.getParameter("password");

        // 根据请求参数执行相应的操作
        if ("register".equals(action)) {
            // 注册用户
            User user = new User();
            user.setUsername(username);
            user.setPassword(password);
            if (userDao.register(user)) {
                response.getWriter().println("注册成功");
            } else {
                response.getWriter().println("注册失败");
            }
        } else if ("login".equals(action)) {
            // 登录验证
            User user = new User();
            user.setUsername(username);
            user.setPassword(password);
            if (userDao.login(user)) {
                response.getWriter().println("登录成功");
            } else {
                response.getWriter().println("登录失败");
            }
        } else {
            response.getWriter().println("无效的请求");
        }
    }
}

5. 创建 JSP 页面

register.jsp

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>用户注册</title>
</head>
<body>
    <h2>用户注册</h2>
    <form action="UserServlet" method="post">
        <input type="hidden" name="action" value="register">
        用户名：<input type="text" name="username"><br>
        密码：<input type="password" name="password"><br>
        <input type="submit" value="注册">
    </form>
</body>
</html>

login.jsp

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>用户登录</title>
</head>
<body>
    <h2>用户登录</h2>
    <form action="UserServlet" method="post">
        <input type="hidden" name="action" value="login">
        用户名：<input type="text" name="username"><br>
        密码：<input type="password" name="password"><br>
        <input type="submit" value="登录">
    </form>
</body>
</html>

6. 部署项目

将 UserServlet、UserDao、User.java、register.jsp 和 login.jsp 等文件放到 Web 项目的相应目录下，然后启动服务器，即可通过访问 register.jsp 和 login.jsp 页面进行注册和登录。