我使用Kundera-Cassandra 3.2并希望使用昆德拉的交易管理。
我的处理方式如下:
EntityManager manager = repo.getEntityManagerFactory().createEntityManager(CassandraRepository.getProperties());
try{
manager.getTransaction().begin();
this.repo.update(account1, manager); //calls the merge method of the Entitymanager
this.repo.save(account2, manager); //calls the persist method of the Entitymanager
manager.getTransaction().commit();
} catch(Exception e){
if(manager.getTransaction().isActive()){
manager.getTransaction().rollback();
}
} finally {
manager.clear();
manager.close();
}
当this.repo.save(account2, manager);
中出现错误时,管理器回滚事务,但不执行更新语句,他为merge方法创建了一个delete语句。原因是,在调用合并方法时,kundera会创建一个insert语句而不是更新。但是如何说昆德拉做出更新以回滚交易还有更新。
日志:
12:42:41.185 [http-bio-8080-exec-3] INFO com.impetus.client.cassandra.CassandraClientBase - Returning delete query DELETE FROM "account" WHERE "id" = 'MCSP-000000000004'.
12:42:41.211 [http-bio-8080-exec-3] INFO com.impetus.client.cassandra.CassandraClientBase - Returning delete query DELETE FROM "account" WHERE "id" = 'MCSP-000000000005'.
编辑(我的存储库):
public class CassandraRepository<T> {
@PersistenceUnit
private EntityManagerFactory entityManagerFactory;
public static Map<String, String> getProperties() {
final Map<String, String> properties = new HashMap<String, String>();
properties.put(CassandraConstants.CQL_VERSION, CassandraConstants.CQL_VERSION_3_0);
return properties;
}
public void update(T entity, EntityManager manager) throws Exception{
try {
manager.merge(entity);
} catch (Exception e) {
e.printStackTrace();
throw e;
}
}
public void save(T entity, EntityManager manager) throws Exception{
try {
manager.persist(entity);
} catch (Exception e) {
e.printStackTrace();
throw e;
}
}
}
答案 0 :(得分:1)
根据JPA,要更新实体,您必须首先将其置于托管状态(通过获取它)
实施例: -
PersonCassandra p = entityManager.find(PersonCassandra.class, "2");
entityManager.getTransaction().begin();
p.setMonth(Month.JAN);
entityManager.merge(p);
entityManager.persist(p3);
entityManager.getTransaction().commit();
问题与INSERT和UPDATE语句不同,因为两者在Cassandra中都是相似的。