数据库引擎不支持事务
在MySQL数据库中有几种引擎(InnoDB,MyISAM,Memory等等),仅仅InnoDB支持事务,如果数据库底层都不支持事务的话,那么再怎么折腾都是白搭.
@transactional加在private方法上
@Transactional只能加在public方法上,如果需要在private方法中加入事务,可以使用Aspect配transactionManager使用.
本类方法调本类另一个方法
例如:
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@Servicepublic class UserServiceImpl implements UserService { @Transactional public void update(User user) { //check updateUserInfo(user); } @Transactional(propagation = Propagation.REQUIRES_NEW) public void updateUser(User user) { // update user }} |
@Transactional(propagation = Propagation.REQUIRES_NEW)是无效的,在Spring中是使用代理的方式实现事务,发生自身调用的时候,没有经过Spring的代理,自然事务失效.
不支持事务
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@Servicepublic class UserServiceImpl implements UserService { @Transactional(propagation = Propagation.NOT_SUPPORTED) public void update(User user) { //do some action }} |
@Transactional(propagation = Propagation.NOT_SUPPORTED)表示如果当前存在事务就挂起,以没有事务的方式运行,主动不支持事务了,那么再怎么操作也是白搭. 此处贴下Spring的传播行为:
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/** * Support a current transaction, create a new one if none exists. * Analogous to EJB transaction attribute of the same name. * <p>This is the default setting of a transaction annotation. */REQUIRED(TransactionDefinition.PROPAGATION_REQUIRED),/** * Support a current transaction, execute non-transactionally if none exists. * Analogous to EJB transaction attribute of the same name. * <p>Note: For transaction managers with transaction synchronization, * PROPAGATION_SUPPORTS is slightly different from no transaction at all, * as it defines a transaction scope that synchronization will apply for. * As a consequence, the same resources (JDBC Connection, Hibernate Session, etc) * will be shared for the entire specified scope. Note that this depends on * the actual synchronization configuration of the transaction manager. * @see org.springframework.transaction.support.AbstractPlatformTransactionManager#setTransactionSynchronization */SUPPORTS(TransactionDefinition.PROPAGATION_SUPPORTS),/** * Support a current transaction, throw an exception if none exists. * Analogous to EJB transaction attribute of the same name. */MANDATORY(TransactionDefinition.PROPAGATION_MANDATORY),/** * Create a new transaction, and suspend the current transaction if one exists. * Analogous to the EJB transaction attribute of the same name. * <p><b>NOTE:</b> Actual transaction suspension will not work out-of-the-box * on all transaction managers. This in particular applies to * {@link org.springframework.transaction.jta.JtaTransactionManager}, * which requires the {@code javax.transaction.TransactionManager} to be * made available to it (which is server-specific in standard Java EE). * @see org.springframework.transaction.jta.JtaTransactionManager#setTransactionManager */REQUIRES_NEW(TransactionDefinition.PROPAGATION_REQUIRES_NEW),/** * Execute non-transactionally, suspend the current transaction if one exists. * Analogous to EJB transaction attribute of the same name. * <p><b>NOTE:</b> Actual transaction suspension will not work out-of-the-box * on all transaction managers. This in particular applies to * {@link org.springframework.transaction.jta.JtaTransactionManager}, * which requires the {@code javax.transaction.TransactionManager} to be * made available to it (which is server-specific in standard Java EE). * @see org.springframework.transaction.jta.JtaTransactionManager#setTransactionManager */NOT_SUPPORTED(TransactionDefinition.PROPAGATION_NOT_SUPPORTED),/** * Execute non-transactionally, throw an exception if a transaction exists. * Analogous to EJB transaction attribute of the same name. */NEVER(TransactionDefinition.PROPAGATION_NEVER),/** * Execute within a nested transaction if a current transaction exists, * behave like PROPAGATION_REQUIRED else. There is no analogous feature in EJB. * <p>Note: Actual creation of a nested transaction will only work on specific * transaction managers. Out of the box, this only applies to the JDBC * DataSourceTransactionManager when working on a JDBC 3.0 driver. * Some JTA providers might support nested transactions as well. * @see org.springframework.jdbc.datasource.DataSourceTransactionManager */NESTED(TransactionDefinition.PROPAGATION_NESTED); |
异常被catch
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@Servicepublic class UserServiceImpl implements UserService { @Transactional public void update(User user) { try{ }catch(Exception e){ log.error(e.getMessage(),e); } }} |
触发回滚的操作是被接收到异常,一般我们会在@Transactional后面加上rollbackFor或者noRollbackForClassName来指明触发回滚的异常,但是如果在代码中给catch了异常,那么对于Spring代理来说就这个方法从头到尾都没有问题,自然不会触发回滚.
异常类型错误
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@Servicepublic class UserServiceImpl implements UserService { @Transactional public void update(User user) { try{ }catch(Exception e){ log.error(e.getMessage(),e); throw new Exception(e.getMessage()); } }} |
以上方式throw new Exception(e.getMessage());事务也是无效的,主要原因是事务回滚的条件是throw 运行时异常(RunTimeException).如果需要其他异常也回滚,需要在@Transactional后面加上rollbackFor或者noRollbackForClassName来指明触发回滚的异常.
没有被Spring管理
不在Spring环境下,自然不受Spring的管理,事务管理器也当然失去了作用.
没有配置TransactionManager
需要对当前数据源配置事务管理器,尤其是在多数据源的情况下.
以上就是Spring事务失效的几种原因的详细内容，更多关于Spring事务失效的资料请关注服务器之家其它相关文章！
原文链接：https://www.bianxiaofeng.com/article/77
