Question

我是Spring的新手，我无法在“必需”模式下进行事务传播。

以下是一个例子：

@Controller
public class ExampleController
{
    @Autowired
    Foo foo;

    @Autowired
    Bar bar;

    @RequestMapping(value = "/example")
    public String submitForm(Model model) throws Exception
    {
        User user = new User("Joe", "Bloggs");
        user = foo.save(user);
        bar.simpleMethod(user);
        return "success";
    }
}

@Repository
public class Foo
{
    // A JPA repository
    private EntityManager em;

    @Transactional(rollbackFor = Exception.class, propagation = Propagation.REQUIRED)
    public User save(User user)
    {
        return this.em.merge(user);
    }

    @PersistenceContext
    void setEntityManager(EntityManager entityManager)
    {
        this.em = entityManager;
    }
}

public class Bar
{
    @Transactional(rollbackFor = Exception.class, propagation = Propagation.REQUIRED)
    public void simpleMethod(User user)
    {
        // Do something...
    }
}

applicationContext.xml（重要位）：

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.1.xsd">
    <context:property-placeholder location="/WEB-INF/jdbc.properties" />

    <bean id="dataSource" class="org.springframework.jdbc.datasource.TransactionAwareDataSourceProxy">
        <constructor-arg>
            <bean class="org.springframework.jdbc.datasource.DriverManagerDataSource">
                <property name="driverClassName" value="${db.driverClassName}" />
                <property name="url" value="${db.url}" />
                <property name="username" value="${db.username}" />
                <property name="password" value="${db.password}" />
            </bean>
        </constructor-arg>
    </bean>

    <bean id="jpaAdapter" class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
        <property name="databasePlatform" value="org.hibernate.dialect.MySQL5Dialect" />
        <property name="showSql" value="${db.showSql}" />
        <property name="generateDdl" value="${db.generateDdl}" />
    </bean>

    <!-- enabling annotation driven configuration /-->
    <context:annotation-config />
    <context:component-scan base-package="my.package" />

    <!-- Instructs the container to look for beans with @Transactional and decorate them -->
    <tx:annotation-driven transaction-manager="transactionManager" proxy-target-class="true" />

    <!-- FactoryBean that creates the EntityManagerFactory  -->
    <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="jpaVendorAdapter" ref="jpaAdapter" />
        <property name="jpaProperties">
            <props>
                <prop key="hibernate.show_sql">true</prop>
                <prop key="hibernate.format_sql">true</prop>
                <prop key="hibernate.hbm2ddl.auto">update</prop>
            </props>
        </property>
        <property name="dataSource" ref="dataSource" />
    </bean>

    <!-- A transaction manager for working with JPA EntityManagerFactories -->
    <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
        <property name="entityManagerFactory" ref="entityManagerFactory" />
    </bean>
</beans>

如果bar.simpleMethod()中出现异常，foo.save(...)不会回滚（或者可能是回滚，但数据库肯定不回滚）。有谁知道为什么？

Answer 1

如果bar.simpleMethod()中出现异常，则foo.save(...)不会回滚

并且它都不应该 - 您已经在Bar.simpleMethod和Foo.save周围单独包装了您的交易注释，因此这些将作为两个单独的交易执行。如果Bar.simpleMethod失败，它将回滚自己的事务，但Foo.save的事务已经提交。没有单一的交易涵盖两者。

您需要将两个操作封装在一个在单个事务中执行两个操作的方法中。最好通过引入一个由控制器调用的额外组件来完成。此方法将使用@Transactional进行注释，并执行Bar.simpleMethod和Foo.save。 @Transactional和Bar.simpleMethod上的Foo.save注释将成为同一整体交易的一部分。

Answer 2

你在这里有两个独立的交易。第一个是提交的，第二个是在异常时回滚的。真的没有什么值得惊讶的。要使这两个调用参与同一个事务，您应该将它们放在一个用@Transactional注释的方法中。

春季交易“必需”传播

2 个答案: