在不同事务中更新和保存相关实体时,服务器将停止工作

我的问题很长,因为在开始的时候我写了一个完整的清单,我正在测试,所以请要么完成阅读,要么走到问题本身的结尾。

我在PostgreSQL数据库中创建表:

create table if not exists users
(
    id bigserial not null
        constraint users_pkey
            primary key,
    name varchar(50),
    is_active boolean not null,
    old_user bigint
        constraint users_users_id_fk
            references users
);

alter table users owner to postgres;

create unique index if not exists users_id_uindex on users (id);

create unique index if not exists users_is_active_idx
    on users (is_active) where (is_active = true);

可能有 只有一个活动用户 .

我创建了Spring boot应用程序。下面是对结构的描述(非常简单),下面是问题本身。

1)实体:

@Data
@NoArgsConstructor
@Entity
@Table(name = "users")
public class User {

    public User(String name, Boolean isActive, User oldUser) {
        this.name = name;
        this.isActive = isActive;
        this.oldUser = oldUser;
    }

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(name = "name")
    private String name;

    @Column(name = "is_active")
    private Boolean isActive;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "old_user")
    private User oldUser;
}

2)存储库:

@Repository
public interface UserRepository extends JpaRepository<User, Long> {
}

3)服务:

@Service
public class UserServiceImpl implements UserService {

    private final UserRepository userRepository;

    public UserServiceImpl(UserRepository userRepository) {
        this.userRepository = userRepository;
    }

    @Override
    public User getOne(Long id) {
        return userRepository.getOne(id);
    }

    @Override
    public User save(User user) {
        return userRepository.save(user);
    }

    @Override
    public User saveAndFlush(User user) {
        return userRepository.saveAndFlush(user);
    }
}

我插入一个活动用户: INSERT INTO "public"."users" ("id", "name", "is_active", "old_user") VALUES (DEFAULT, 'FirstUser', true, NULL)

现在我想插入第二个用户(活动),但来自应用程序:

@Slf4j
@Component
public class TestBean implements CommandLineRunner {

    private final UserService userService;

    public TestBean(UserService userService) {
        this.userService = userService;
    }

    @Override
    @Transactional
    public void run(String... args) throws Exception {
        log.info("Start...");

        User first = userService.getOne(1L);
        User secondUser = new User("SecondUser", true, first);
        userService.saveAndFlush(secondUser);
    }
}

如果运行服务器,则会出现异常:o rg.postgresql.util.PSQLException: ERROR: duplicate key value violates unique constraint "users_is_active_idx"

要解决这个问题,我必须先停用旧用户,然后激活新用户。但这样做行不通,所以在激活新用户之前,我必须将其刷新到上下文:

    User first = userService.getOne(1L);
    first.setIsActive(false);
    userService.saveAndFlush(first);
    User secondUser = new User("SecondUser", true, first);
    userService.saveAndFlush(secondUser);

这个解决方案很好。但现在我为服务添加了新方法:

@Override
@Transactional(propagation = Propagation.REQUIRES_NEW)
public User saveInRequiredNew(User user) {
    return userRepository.saveAndFlush(user);
}

并尝试使用以下方法保存用户:

    User first = userService.getOne(1L);
    first.setIsActive(false);
    userService.saveAndFlush(first);
    User secondUser = new User("SecondUser", true, first);
    User user = userService.saveInRequiredNew(secondUser);
    log.info(String.valueOf(user.getId()));

在这种情况下,当我打电话给 saveInRequiredNew 方法我的应用程序没有抛出异常和结果。它只是停止工作。在实际应用程序中,我的逻辑是建立的,因此我必须将对象保存在 Propagation.REQUIRES_NEW .

我的问题 -为什么会发生这种情况?解决办法是什么?可以同时更新两个实体(一个事务中的旧用户和新用户( 传播。需要新的 ). 我不知道这是否正确)