我用的是Spring Boot 2.4.1 与 spring-boot-starter-data-cassandra .
下面是repository类

@Repository
public interface UserRepository extends CassandraRepository<UserModel, String> {

}

下面是pojo

@Table("user")
public class UserModel {

    @PrimaryKeyColumn(name = "userid", type = PrimaryKeyType.PARTITIONED)
    private String userId;

    @Column("emailid")
    private String emailId;

    @Column("phonenumber")
    private String phoneNumber;

    //getters and setters
    }

下面是调用update方法的类：

@Component
public class UpdateTask {

    @Autowired
    private UserRepository userRepository;

    public void removePhoneNumber(UserModel t) {
        t.setPhoneNumber(null);
        userRepository.save(t);
    }

}

问题是我想将电话号码字段更新为 null 因为用户想要删除他们的电话号码。但是cassandra忽略了空值集。如何在cassandra中将值显式设置为null？