Java 嵌套事务理论上可用，但未使用

我试图阻止在导入服务中创建多个对象，该导入服务在多个线程的多个服务器节点上运行。我这样做的唯一机会似乎是对数据库使用一个独特的约束，这是唯一的一个点，所有的东西都再次聚集在一起

我的服务现在尝试创建对象，并接收DataIntegrityViolationException。然后查询并使用另一个进程已经创建的对象。到目前为止，一切顺利

但该对象的查询被Postgres拒绝，错误消息为

SQL状态[25P02]；错误代码[0]

表示当前事务已中断

简而言之，我的代码如下所示：

@Transactional
public void connectToCollections(Product product) {
    for (Collection coll : product.getCollections()) {
        Set<CollectionMaster> collCandidates = new HashSet<CollectionMaster>();
        CollectionMaster oldMaster = coll.getMaster();

        newMaster = collectionMasterRepository.findByTitleAndSubtitle(product, coll);

        if (newMaster == null) {
            newMaster = createNewMaster(product,coll);
            if(newMaster == null) {
                // Maybe already created by another process; search again!
                newMaster = collectionMasterRepository.findByTitleAndSubtitle(product, coll);
            }
        }

        // Do something with newMaster
    }
}

private CollectionMaster createNewMaster(Product product, Collection coll) {
    CollectionMaster oldMaster = coll.getMaster();
    CollectionMaster newMaster = null;

    oldMaster.setCreatedBy(product.getCreatedBy());
    oldMaster.setLastModifiedBy(product.getCreatedBy());

    try {
        newMaster = create(oldMaster);
    }
    catch(DataIntegrityViolationException e) {
        return null;
    }
    coll.setMaster(newMaster);

    return newMaster;
}


@Transactional(propagation=Propagation.NESTED)
public CollectionMaster create(CollectionMaster collMaster) {
    CollectionMaster result = null;
    result = collectionMasterRepository.saveAndFlush(collMaster);
    return result;
}

<hibernate.version>4.1.7.Final</hibernate.version>
<postgresql.version>9.3-1102-jdbc41</postgresql.version>
<commons-dbcp2.version>2.0.1</commons-dbcp2.version>
<spring.version>3.2.9.RELEASE</spring.version>
<spring-data-jpa.version>1.6.0.RELEASE</spring-data-jpa.version>
<aspectj.version>1.8.0</aspectj.version>

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-core</artifactId>
    <version>${spring.version}</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-beans</artifactId>
    <version>${spring.version}</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-orm</artifactId>
    <version>${spring.version}</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-jdbc</artifactId>
    <version>${spring.version}</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-tx</artifactId>
    <version>${spring.version}</version>
</dependency>
<dependency>
    <groupId>org.springframework.data</groupId>
    <artifactId>spring-data-jpa</artifactId>
    <version>${spring-data-jpa.version}</version>
    <exclusions>
        <exclusion>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
        </exclusion>
        <exclusion>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aop</artifactId>
        </exclusion>
        <exclusion>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
        </exclusion>
        <exclusion>
            <groupId>org.springframework</groupId>
            <artifactId>spring-expression</artifactId>
        </exclusion>
        <exclusion>
            <groupId>org.springframework</groupId>
            <artifactId>spring-orm</artifactId>
        </exclusion>
        <exclusion>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
        </exclusion>
        <exclusion>
            <groupId>org.springframework</groupId>
            <artifactId>spring-tx</artifactId>
        </exclusion>
    </exclusions>
</dependency>
<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-dbcp2</artifactId>
    <version>${commons-dbcp2.version}</version>
</dependency>
<dependency>
    <groupId>org.hibernate</groupId>
    <artifactId>hibernate-core</artifactId>
    <version>${hibernate.version}</version>
    <exclusions>
        <exclusion>
            <groupId>cglib</groupId>
            <artifactId>cglib</artifactId>
        </exclusion>
        <exclusion>
            <groupId>net.sf.ehcache</groupId>
            <artifactId>ehcache</artifactId>
        </exclusion>
        <exclusion>
            <groupId>asm</groupId>
            <artifactId>asm</artifactId>
        </exclusion>
        <exclusion>
            <groupId>asm</groupId>
            <artifactId>asm-attrs</artifactId>
        </exclusion>
        <exclusion>
            <groupId>javax.transaction</groupId>
            <artifactId>jta</artifactId>
        </exclusion>
    </exclusions>
</dependency>
<dependency>
    <groupId>org.hibernate</groupId>
    <artifactId>hibernate-entitymanager</artifactId>
    <version>${hibernate.version}</version>
    <exclusions>
        <exclusion>
            <groupId>cglib</groupId>
            <artifactId>cglib</artifactId>
        </exclusion>
        <exclusion>
            <groupId>dom4j</groupId>
            <artifactId>dom4j</artifactId>
        </exclusion>
    </exclusions>
</dependency>
<dependency>
    <groupId>javax.transaction</groupId>
    <artifactId>transaction-api</artifactId>
    <version>1.1</version>
</dependency>
<dependency>
    <groupId>org.postgresql</groupId>
    <artifactId>postgresql</artifactId>
    <version>${postgresql.version}</version>
</dependency>

@Transactional
公共无效连接集合（产品）{
for（Collection coll:product.getCollections（））{
Set collpardidates=newhashset（）；
CollectionMaster oldMaster=coll.getMaster（）；
newMaster=collectionMasterRepository.findbytileandsubtitle（产品，coll）；
if（newMaster==null）{
newMaster=createNewMaster（产品，coll）；
if（newMaster==null）{
//可能已由另一个进程创建；请再次搜索！
newMaster=collectionMasterRepository.findbytileandsubtitle（产品，coll）；
}
}
//和newMaster做点什么
}
}
private CollectionMaster createNewMaster（产品-产品，集合库）{
CollectionMaster oldMaster=coll.getMaster（）；
CollectionMaster newMaster=null；
setCreatedBy（product.getCreatedBy（））；
setLastModifiedBy（product.getCreatedBy（））；
试一试{
newMaster=create（oldMaster）；
}
捕获（DataIntegrityViolationException e）{
返回null；
}
coll.setMaster（newMaster）；
返回newMaster；
}
@事务（传播=传播.嵌套）
公共CollectionMaster创建（CollectionMaster collMaster）{
CollectionMaster结果=空；
结果=collectionMasterRepository.saveAndFlush（collMaster）；
返回结果；
}

入口点是connectToCollections。查询CollectionMaster，如果未找到，则尝试创建，如果不成功，则再次查询。 似乎忽略了嵌套传播（或REQUIRES_NEW）的@Transactional属性，并且没有在数据库上设置或使用保存点，通常使用的技术堆栈应该能够这样做。我错过了什么

pom.xml的相关部分如下所示：

@Transactional
public void connectToCollections(Product product) {
    for (Collection coll : product.getCollections()) {
        Set<CollectionMaster> collCandidates = new HashSet<CollectionMaster>();
        CollectionMaster oldMaster = coll.getMaster();

        newMaster = collectionMasterRepository.findByTitleAndSubtitle(product, coll);

        if (newMaster == null) {
            newMaster = createNewMaster(product,coll);
            if(newMaster == null) {
                // Maybe already created by another process; search again!
                newMaster = collectionMasterRepository.findByTitleAndSubtitle(product, coll);
            }
        }

        // Do something with newMaster
    }
}

private CollectionMaster createNewMaster(Product product, Collection coll) {
    CollectionMaster oldMaster = coll.getMaster();
    CollectionMaster newMaster = null;

    oldMaster.setCreatedBy(product.getCreatedBy());
    oldMaster.setLastModifiedBy(product.getCreatedBy());

    try {
        newMaster = create(oldMaster);
    }
    catch(DataIntegrityViolationException e) {
        return null;
    }
    coll.setMaster(newMaster);

    return newMaster;
}


@Transactional(propagation=Propagation.NESTED)
public CollectionMaster create(CollectionMaster collMaster) {
    CollectionMaster result = null;
    result = collectionMasterRepository.saveAndFlush(collMaster);
    return result;
}

<hibernate.version>4.1.7.Final</hibernate.version>
<postgresql.version>9.3-1102-jdbc41</postgresql.version>
<commons-dbcp2.version>2.0.1</commons-dbcp2.version>
<spring.version>3.2.9.RELEASE</spring.version>
<spring-data-jpa.version>1.6.0.RELEASE</spring-data-jpa.version>
<aspectj.version>1.8.0</aspectj.version>

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-core</artifactId>
    <version>${spring.version}</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-beans</artifactId>
    <version>${spring.version}</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-orm</artifactId>
    <version>${spring.version}</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-jdbc</artifactId>
    <version>${spring.version}</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-tx</artifactId>
    <version>${spring.version}</version>
</dependency>
<dependency>
    <groupId>org.springframework.data</groupId>
    <artifactId>spring-data-jpa</artifactId>
    <version>${spring-data-jpa.version}</version>
    <exclusions>
        <exclusion>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
        </exclusion>
        <exclusion>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aop</artifactId>
        </exclusion>
        <exclusion>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
        </exclusion>
        <exclusion>
            <groupId>org.springframework</groupId>
            <artifactId>spring-expression</artifactId>
        </exclusion>
        <exclusion>
            <groupId>org.springframework</groupId>
            <artifactId>spring-orm</artifactId>
        </exclusion>
        <exclusion>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
        </exclusion>
        <exclusion>
            <groupId>org.springframework</groupId>
            <artifactId>spring-tx</artifactId>
        </exclusion>
    </exclusions>
</dependency>
<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-dbcp2</artifactId>
    <version>${commons-dbcp2.version}</version>
</dependency>
<dependency>
    <groupId>org.hibernate</groupId>
    <artifactId>hibernate-core</artifactId>
    <version>${hibernate.version}</version>
    <exclusions>
        <exclusion>
            <groupId>cglib</groupId>
            <artifactId>cglib</artifactId>
        </exclusion>
        <exclusion>
            <groupId>net.sf.ehcache</groupId>
            <artifactId>ehcache</artifactId>
        </exclusion>
        <exclusion>
            <groupId>asm</groupId>
            <artifactId>asm</artifactId>
        </exclusion>
        <exclusion>
            <groupId>asm</groupId>
            <artifactId>asm-attrs</artifactId>
        </exclusion>
        <exclusion>
            <groupId>javax.transaction</groupId>
            <artifactId>jta</artifactId>
        </exclusion>
    </exclusions>
</dependency>
<dependency>
    <groupId>org.hibernate</groupId>
    <artifactId>hibernate-entitymanager</artifactId>
    <version>${hibernate.version}</version>
    <exclusions>
        <exclusion>
            <groupId>cglib</groupId>
            <artifactId>cglib</artifactId>
        </exclusion>
        <exclusion>
            <groupId>dom4j</groupId>
            <artifactId>dom4j</artifactId>
        </exclusion>
    </exclusions>
</dependency>
<dependency>
    <groupId>javax.transaction</groupId>
    <artifactId>transaction-api</artifactId>
    <version>1.1</version>
</dependency>
<dependency>
    <groupId>org.postgresql</groupId>
    <artifactId>postgresql</artifactId>
    <version>${postgresql.version}</version>
</dependency>

4.1.7.Final
9.3-1102-jdbc41
2.0.1
3.2.9.1发布
1.6.0.1发布
1.8.0
org.springframework
弹簧芯
${spring.version}
org.springframework
春豆
${spring.version}
org.springframework
春季甲虫
${spring.version}
org.springframework
SpringJDBC
${spring.version}
org.springframework
德克萨斯州春季
${spring.version}
org.springframework.data
spring数据jpa
${spring数据jpa.version}
org.springframework
春豆
org.springframework
春季aop
org.springframework
spring上下文
org.springframework
弹簧式
org.springframework
春季甲虫
org.springframework
SpringJDBC
org.springframework
德克萨斯州春季
org.apache.commons
commons-dbcp2
${commons-dbcp2.version}
org.hibernate
冬眠核心
${hibernate.version}
cglib
cglib
net.sf.ehcache
ehcache
asm
asm
asm
asm属性
javax.transaction
jta
org.hibernate
休眠实体管理器
${hibernate.version}
cglib
cglib
dom4j
dom4j
javax.transaction
事务api
1.1
org.postgresql
postgresql
${postgresql.version}

最后是Spring应用程序上下文的相关部分：

<bean id="dataSource" class="org.apache.commons.dbcp2.BasicDataSource" destroy-method="close">
    <property name="driverClassName" value="${database.driverClassName}" />
    <property name="url" value="${database.url}" />
    <property name="username" value="${database.username}" />
    <property name="password" value="${database.password}" />
</bean>

<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
    <property name="dataSource" ref="dataSource" />
    <property name="jpaVendorAdapter">
        <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
            <property name="generateDdl" value="true" />
            <property name="database" value="${database.dialect}" />
        </bean>
    </property>
    <property name="jpaPropertyMap">
        <map>
            <entry key="javax.persistence.validation.factory" value-ref="validator" />
            <entry key="hibernate.show_sql" value="${hibernate.show_sql}"/>
            <entry key="hibernate.hbm2ddl.auto" value="${hibernate.hbm2ddl}"/>
            <entry key="org.hibernate.envers.track_entities_changed_in_revision" value="true"/>
        </map>
    </property>
    <property name="persistenceUnitName" value="mvb.vlx.model" />
    <property name="persistenceUnitManager" ref="persistenceUnitManager" />
</bean>

<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
    <property name="entityManagerFactory" ref="entityManagerFactory" />
    <property name="nestedTransactionAllowed" value="true"/>
</bean>

<tx:annotation-driven transaction-manager="transactionManager" mode="aspectj" />

---

Java版本是jdk1.7.0_40。免责声明：我从未使用过Postgres。嵌套事务支持在数据库供应商和驱动程序之间可能会有很大差异

然而，我认为问题可能在于：

try {
    ...
} catch(DataIntegrityViolationException e) {
    return null;
}

当创建失败时，数据库将事务标记为失败，但在Java中忽略了这一点。因此，我怀疑当你尝试实施它时，它会失败

我认为您的选择是要么失败并重试整个块（connectToCollections（）），要么在新的/嵌套的事务中执行createNewMaster（）

如果使用后者，请记住@Transactional在私有方法上不起作用，因为代理是如何创建的。您仍然可以通过编程方式完成，Spring的TransactionTemplate和RetryTemplate是实现这一点的优秀工具

---

另外，我也不确定我是否理解正确，但如果你的意思是将“嵌套”放在connectToCollections（）上，那当然没有什么区别（你可能希望嵌套createNewMaster（））。

@Transactional on private方法与我们使用的aspectj一起工作。当我显式地自动连接事务管理器并手动启动事务时，即使配置了HibernateDialect，也会出现异常“JPA方言不支持嵌套事务”。这仍然是一个奇怪的现象…直到最后我都无法创建嵌套的或“真正”的新事务。但是RetryTemplate完成了tri