java 4@事务嵌套事务问题
java 4@事务嵌套事务问题
提问于 2016-04-20 08:42:20
我有以下课程：
@Transactional
public class MyClass{
@Transactional(propagation=Propagation.REQUIRES_NEW)
public void method1(){
....
myDao.update(entity);
}
public void method2(){
method1();
//I need to be sure that data was persisted to DB and find the entity by id
MyEntity ent=myDao.find(entityId);
//entity is not updated here
}
}但实际上，我无法从method2中的DB读取更新的实体。如何做到这一点？我需要在method2中在method1()调用之后更新值，因此应该提交method1中的事务，并且结果是可见的。怎么做？
回答 2
Stack Overflow用户
回答已采纳
发布于 2016-04-20 08:50:41
您必须在另一个类中执行此操作，因为在调用本地方法时不遵守@Transactional (这取决于Spring代理的工作方式，本地方法调用this绕过事务代理)。
解决方案可能如下所示：
class Wrapper {
public void performAction() {
myClass.method1();
myClass.find(entityId);
}
}Stack Overflow用户
发布于 2016-04-20 14:04:35
我重新创建了类似于(嵌入式数据库)的场景:首先，我向数据库添加了如下内容：
public void initialize() {
Sample startEntity = new Sample();
startEntity.setId(1);
startEntity.setName("Start name");
sampleRepository.saveSample(startEntity);
sampleRepository.flush(); // <-- just to make sure scenario is recreated
sampleRepository.clear(); // same as above
LOGGER.info(sampleRepository.findSampleById(1));
sampleRepository.clear(); // same as above above :D
}在此之后，我们在数据库中得到一个实体样本(所有事务都结束，缓存被清除)；
控制台：
Hibernate: insert into sample (name, id) values (?, ?)
Hibernate: select sample0_.id as id1_0_0_, sample0_.name as name2_0_0_ from sample sample0_ where sample0_.id=?
2016-04-20 15:58:21.762 INFO 5764 --- [ main] com.patrykwoj.service.BasicServiceTest : Sample [id=1, name=Start name]现在你的例子是：
@Transactional
@Component
public class SampleService {
private static final Logger LOGGER = Logger.getLogger(SampleService.class);
@Autowired
SampleRepository sampleRepository;
@Transactional (propagation = Propagation.REQUIRES_NEW)
public void method1() {
Sample someSample = new Sample();
someSample.setId(1);
someSample.setName("TestSample before update but after create");
sampleRepository.updateSample(someSample);
}
public void method2() {
method1();
// I need to be sure that data was persisted to DB and find the entity by id
Sample someSampleAfterUpdate = sampleRepository.findSampleById(1); //I believe that at that point sample is found in L-1 cache not in db directry.
// entity is not updated here
LOGGER.info(someSampleAfterUpdate); //in this point, transaction is not over yet, so you wont notice change in database..
}
}然后从代码执行中获得控制台：
Hibernate: select sample0_.id as id1_0_0_, sample0_.name as name2_0_0_ from sample sample0_ where sample0_.id=?
2016-04-20 16:02:17.903 INFO 5044 --- [ main] com.patrykwoj.service.SampleService : Sample [id=1, name=TestSample before update but after create]
Hibernate: update sample set name=? where id=?
2016-04-20 16:02:17.903 INFO 5044 --- [ main] com.patrykwoj.StackOverfloApplication : Method2 is over主修班：
@Override
public void run(String... strings) throws Exception {
basicServiceTest.initialize();
sampleService.method2();
LOGGER.info("Method2 is over");
}在我看来一切看起来都很好。它果然起作用了。我在您的代码中做了一些评论，但是控制台输出应该是清楚的。
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原文链接：
https://stackoverflow.com/questions/36738347
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