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乐观锁定不工作的Spring数据JPA

spring-data-jpa spring-boot hibernate spring java

damian · 技术社区 · 6 年前

我无法在springdatajpa的springboot2项目上工作。我有一个测试,在不同的线程中运行两个简单的更新,但是它们都是成功的(没有乐观的锁异常),其中一个更新被另一个覆盖。

(请看下面的编辑)

这是我的实体:

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

  @Column(name = "UserID")
  @Id
  @GeneratedValue(strategy = GenerationType.IDENTITY)
  private Integer id;
  @Column(name = "FirstName")
  @NotBlank()
  private String fistName;
  @Column(name = "LastName")
  @NotBlank
  private String lastName;
  @Column(name = "Email")
  @NotBlank
  @Email
  private String email;
  @Version
  @Column(name = "Version")
  private long version;

  // getters & setters
}

这是我的存储库:

public interface UserRepository extends JpaRepository<User, Integer> {
}

@Service
public class UserService {

  @Transactional(propagation = Propagation.REQUIRES_NEW)
  public User updateUser(User user)
        throws UserNotFoundException {
    final Optional<User> oldUserOpt =  userRepository.findById(user.getId());
    User oldUser = oldUserOpt
            .orElseThrow(UserNotFoundException::new);

        logger.debug("udpateUser(): saving user. {}", user.toString());
        oldUser.setFistName(user.getFistName());
        oldUser.setLastName(user.getLastName());
        oldUser.setEmail(user.getEmail());
        return userRepository.save(oldUser);        
  }
}

最后,我的测试是:

@SpringBootTest
@AutoConfigureMockMvc
@RunWith(SpringRunner.class)
@DirtiesContext(classMode = DirtiesContext.ClassMode.AFTER_EACH_TEST_METHOD)
public class UserControllerIntegrationTest {

  @Test
  public void testConcurrentUpdate() throws Exception {

    String body1 = "{\"fistName\":\"John\",\"lastName\":\"Doe\",\"email\":\"johno@gmail.com\"}";
    String body2 = "{\"fistName\":\"John\",\"lastName\":\"Watkins\",\"email\":\"johno@gmail.com\"}";

    Runnable runnable1 = () -> {
        try {
            mvc.perform(put("/v1/users/1")
                    .contentType(MediaType.APPLICATION_JSON)
                    .characterEncoding("UTF-8")
                    .content(body1));
        } catch (Exception e) {
            System.out.println("exception in put " + e);
        }
    };

    Runnable runnable2 = () -> {
        try {
            mvc.perform(put("/v1/users/1")
                    .contentType(MediaType.APPLICATION_JSON)
                    .characterEncoding("UTF-8")
                    .content(body2));
        } catch (Exception e) {
            System.out.println("exception in put " + e);
        }
    };

    Thread t1 = new Thread(runnable1);
    Thread t2 = new Thread(runnable2);

    t1.start();
    t2.start();
    t1.join();
    t2.join();

    System.out.println("user after updates: " + userRepository.findById(1).get().toString());
  }
}

插入用户(用户名、名字、姓氏、电子邮件、版本)

这些是日志。我注意到在sql中正在检查和设置版本,所以工作正常。update语句在事务结束时执行,但两个事务都成功执行,没有异常。

顺便说一下,我试图重写存储库中的save方法来添加@Lock(LockModeType.com)但一切都没有改变。

[       Thread-4] c.u.i.service.UserService     : updateUser(): saving user. User{id=1, fistName='John', lastName='Doe', email='johno@gmail.com', version=1}
[       Thread-5] c.u.i.service.UserService     : updateUser(): saving user. User{id=1, fistName='John', lastName='Watkins', email='johno@gmail.com', version=1}
[       Thread-5] o.s.t.i.TransactionInterceptor           : Getting transaction for [com.company.app.service.UserService.updateUser]
[       Thread-4] o.s.t.i.TransactionInterceptor           : Getting transaction for [com.company.app.service.UserService.updateUser]
[       Thread-4] o.s.t.i.TransactionInterceptor           : Getting transaction for [org.springframework.data.jpa.repository.support.SimpleJpaRepository.findById]
[       Thread-5] o.s.t.i.TransactionInterceptor           : Getting transaction for [org.springframework.data.jpa.repository.support.SimpleJpaRepository.findById]
[       Thread-4] org.hibernate.SQL                        : select user0_.UserID as Use1_3_0_, user0_.Email as Email2_3_0_, user0_.FirstName as FirstNam4_3_0_, user0_.LastName as LastName5_3_0_, user0_.Version as Version9_3_0_ from User user0_ where user0_.UserID=1
[       Thread-5] org.hibernate.SQL                        : select user0_.UserID as Use1_3_0_, user0_.Email as Email2_3_0_, user0_.FirstName as FirstNam4_3_0_, user0_.LastName as LastName5_3_0_, user0_.Version as Version9_3_0_ from User user0_ where user0_.UserID=1
[       Thread-5] o.s.t.i.TransactionInterceptor           : Completing transaction for [org.springframework.data.jpa.repository.support.SimpleJpaRepository.findById]
[       Thread-4] o.s.t.i.TransactionInterceptor           : Completing transaction for [org.springframework.data.jpa.repository.support.SimpleJpaRepository.findById]
[       Thread-5] o.s.t.i.TransactionInterceptor           : Getting transaction for [org.springframework.data.jpa.repository.support.SimpleJpaRepository.save]
[       Thread-4] o.s.t.i.TransactionInterceptor           : Getting transaction for [org.springframework.data.jpa.repository.support.SimpleJpaRepository.save]
[       Thread-4] o.s.t.i.TransactionInterceptor           : Completing transaction for [org.springframework.data.jpa.repository.support.SimpleJpaRepository.save]
[       Thread-5] o.s.t.i.TransactionInterceptor           : Completing transaction for [org.springframework.data.jpa.repository.support.SimpleJpaRepository.save]
[       Thread-4] o.s.t.i.TransactionInterceptor           : Completing transaction for [com.company.app.service.UserService.updateUser]
[       Thread-5] o.s.t.i.TransactionInterceptor           : Completing transaction for [com.company.app.service.UserService.updateUser]
[       Thread-5] org.hibernate.SQL                        : update User set Email=johno@gmail.com, FirstName=John, LastName=Watkins, Version=2 where UserID=1 and Version=1
[       Thread-4] org.hibernate.SQL                        : update User set Email=johno@gmail.com, FirstName=John, LastName=Doe, Version=2 where UserID=1 and Version=1
user after updates: User{id=1, fistName='John', lastName='Watkins', email='johno@gmail.com', version=2}

我认为问题是因为插入是在同一时间完成的。我在调用save()之前在服务中添加了以下代码:

double random = Math.random();
long wait = (long) (random * 500);
logger.debug("waiting {} ms", wait);
try {
    Thread.sleep(wait);
} catch (InterruptedException e) {
    e.printStackTrace();
}

使用这段代码,我总是得到乐观锁异常,因为插入不是同时执行的。没有这种丑陋的解决办法,我从来都不是例外。有办法解决吗?(此解决方案除外)。或者我不应该担心生产中发生的这种情况?

0 回复 | 直到 6 年前

-2

Cristian Colorado 6 年前

你可以利用 ExecutorService 管理多线程和 CyclicBarrier 为了同步线程执行(或者至少缩短线程之间的执行时间间隔)。

我举了个例子打电话给你 UserService 班级:

public interface UserRepository extends CrudRepository<User, Long> {

  @Lock(value = LockModeType.OPTIMISTIC)
  Optional<User> findById(Long id);
}

JUnit测试用例

// Create a Callable that updates the user
  public Callable<Boolean> createCallable(User user, int tNumber, CyclicBarrier gate) throws OptimisticLockingFailureException {
    return () -> {
      // Create POJO to update, we add a number to string fields
      User newUser = new User(user.getId(),
              user.getFistName() + "[" + tNumber + "]",
              user.getLastName()  + "[" + tNumber + "]",
              user.getEmail());

      // Hold on until all threads have created POJO
      gate.await();

      // Once CyclicBarrier is open, we run update
      User updatedUser = userService.updateUser(newUser);

      return true;
    };
  }

  @Test(expected = ObjectOptimisticLockingFailureException.class)
  public void userServiceShouldThrowOptimisticLockException() throws Throwable {
    final int threads = 2; // We need 2 threads
    final CyclicBarrier gate = new CyclicBarrier(threads); // Barrier will open once 2 threads are awaiting
    ExecutorService executor = Executors.newFixedThreadPool(threads);

    // Create user for testing
    User user = new User("Alfonso", "Cuaron", "alfonso@ac.com");
    User savedUser = userRepository.save(user);

    // Create N threads that calls to service
    List<Callable<Boolean>> tasks = new ArrayList<>();
    for(int i = 0; i < threads; i++) {
      tasks.add(createCallable(savedUser, i, gate));
    }

    // Invoke N threads
    List<Future<Boolean>> result = executor.invokeAll(tasks);

    // Iterate over the execution results to browse exceptions
    for (Future<Boolean> r : result) {
      try {
        Boolean temp = r.get();
        System.out.println("returned " + temp);
      } catch (ExecutionException e) {
        // Re-throw the exception that ExecutorService catch
        throw e.getCause();
      }
    }
  }

我们使用 Callable Exceptions 我们可以从中恢复过来 执行服务

注意,线程调用和save语句之间的指令越多,它们不同步导致OptimisticLockException的可能性就越大。由于您将调用控制器,我建议增加线程数量以获得更好的机会。