mysql数据库实体类

// 示例代码
public class User {
    private Integer id;
    private String username;
    private String email;
    // 省略getter和setter方法
}

// 示例代码
String sql = "SELECT * FROM user WHERE id = ?";
try (PreparedStatement ps = connection.prepareStatement(sql)) {
    ps.setInt(1, userId);
    ResultSet rs = ps.executeQuery();
    if (rs.next()) {
        User user = new User();
        user.setId(rs.getInt("id"));
        user.setUsername(rs.getString("username"));
        user.setEmail(rs.getString("email"));
    }
} catch (SQLException e) {
    e.printStackTrace();
}

// 示例代码
String sql = "UPDATE user SET username = ?, email = ? WHERE id = ?";
try (PreparedStatement ps = connection.prepareStatement(sql)) {
    ps.setString(1, newUsername);
    ps.setString(2, newEmail);
    ps.setInt(3, userId);
    int affectedRows = ps.executeUpdate();
    if (affectedRows > 0) {
        System.out.println("更新成功");
    } else {
        System.out.println("更新失败");
    }
} catch (SQLException e) {
    e.printStackTrace();
}