mysql 事务回滚锁表时间 mysql的事务回滚

原文：

  mysql的引擎常用的有两个，一个MyISAM，另一个是InnoDB，mysql默认的为MyISAM,而InnoDB才是支持事务的。所以一般需要修改下，如何修改就不说了。

   事务需要依赖数据库，好久没使用声明式事务，今天试了下。关键配置如下。

< tx:advice id="transactionAdvice" transaction-manager="transactionManager"> < tx:attributes > < tx:method name="add*" propagation="REQUIRED" /> < tx:method name="append*" propagation="REQUIRED" /> < tx:method name="insert*" propagation="REQUIRED" /> < tx:method name="save*" propagation="REQUIRED" /> < tx:method name="update*" propagation="REQUIRED" /> < tx:method name="modify*" propagation="REQUIRED" /> < tx:method name="edit*" propagation="REQUIRED" /> < tx:method name="delete*" propagation="REQUIRED" /> < tx:method name="remove*" propagation="REQUIRED" /> < tx:method name="tx*" propagation="REQUIRED" /> < tx:method name="repair" propagation="REQUIRED" /> < tx:method name="delAndRepair" propagation="REQUIRED" /> < tx:method name="get*" propagation="SUPPORTS" /> < tx:method name="find*" propagation="SUPPORTS" /> < tx:method name="load*" propagation="SUPPORTS" /> < tx:method name="search*" propagation="SUPPORTS" /> < tx:method name="datagrid*" propagation="SUPPORTS" /> < tx:method name="*" propagation="SUPPORTS" /> </ tx:attributes > </ tx:advice > < aop:config > < aop:pointcut id="transactionPointcut" expression="execution(* com.wondersgroup.employeeBenefits.*.*.service..*Impl.*(..))" /> <!-- com.wondersgroup.benefit.*.core.service..*Impl.*(..) --> < aop:advisor pointcut-ref="transactionPointcut" advice-ref="transactionAdvice" /> </ aop:config >

　　事务配置好之后再service中手动抛了个exception，结果没有回滚，service方法如下

@Override public int saveBudgetApplyInfo(BudgetApplyInfo budgetApplyInfo) throws Exception { budgetApplyInfoMapper.insert(budgetApplyInfo); if ( 1 == 1 ){ throw new Exception(); } return 1 ; }

　　跟着断点一步步进去查看原因

在

TransactionAspectSupport中发现这样一个方法

/** * Handle a throwable, completing the transaction. * We may commit or roll back, depending on the configuration. * @param txInfo information about the current transaction * @param ex throwable encountered */ protected void completeTransactionAfterThrowing(TransactionInfo txInfo, Throwable ex) { if (txInfo != null && txInfo.hasTransaction()) { if (logger.isTraceEnabled()) { logger.trace( "Completing transaction for [" + txInfo.getJoinpointIdentification() + "] after exception: " + ex); } if (txInfo.transactionAttribute.rollbackOn(ex)) { try { txInfo.getTransactionManager().rollback(txInfo.getTransactionStatus()); } catch (TransactionSystemException ex2) { logger.error( "Application exception overridden by rollback exception" , ex); ex2.initApplicationException(ex); throw ex2; } catch (RuntimeException ex2) { logger.error( "Application exception overridden by rollback exception" , ex); throw ex2; } catch (Error err) { logger.error( "Application exception overridden by rollback error" , ex); throw err; } } else { // We don't roll back on this exception. // Will still roll back if TransactionStatus.isRollbackOnly() is true. try { txInfo.getTransactionManager().commit(txInfo.getTransactionStatus()); } catch (TransactionSystemException ex2) { logger.error( "Application exception overridden by commit exception" , ex); ex2.initApplicationException(ex); throw ex2; } catch (RuntimeException ex2) { logger.error( "Application exception overridden by commit exception" , ex); throw ex2; } catch (Error err) { logger.error( "Application exception overridden by commit error" , ex); throw err; } } } }

　　上面的方法中有这么一段

txInfo.transactionAttribute.rollbackOn(ex)，这里是判断是否需要执行回滚操作的，跟踪rollbackOn方法最后会执行到

DefaultTransactionAttribute中的rollbackOn方法

/** * The default behavior is as with EJB: rollback on unchecked exception. * Additionally attempt to rollback on Error. * <p>This is consistent with TransactionTemplate's default behavior. */ public boolean rollbackOn(Throwable ex) { return (ex instanceof RuntimeException || ex instanceof Error); }

　　看到这里，应该都清楚了。。。自己主动抛异常Exception是不对的。这里只捕获运行时异常

RuntimeException 及Error，所以我们测试时不可以直接抛Exception，而应该换成

RuntimeException 。当然。也可在xml中指定rollback- for

< tx:method name="add*" propagation="REQUIRED" rollback-for="Exception" />

　　最后：个人还是比较喜欢基于注解的事务处理

如果还不行，请接着看下面这篇：

最近做一个项目，项目的框架采用是Spring3MVC+MyBatis3.1。可是在开发过程中发现配置的事务不管用。

出现这个问题的现象是用Junit调试事务管用，而部署到Tomcat中就不管用了。先看看事务的配置：

<!--proxy-target-class="true"强制使用cglib代理   如果为false则spring会自动选择-->
<aop:aspectj-autoproxy proxy-target-class="true"/><!-- Transaction manager for a single JDBC DataSource -->
 <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
     <property name="dataSource" ref="dataSource" />
 </bean>

 <tx:advice id="txAdvice" transaction-manager="transactionManager">
     <tx:attributes>
         <tx:method name="save*" propagation="REQUIRED"/>
     </tx:attributes>
 </tx:advice>


 <aop:config>
 <aop:pointcut expression="execution(public * com.luyou.platform.service.impl.*Impl.*(..))" id="pointcut"/>
 <aop:advisor advice-ref="txAdvice" pointcut-ref="pointcut"/>
 </aop:config>

采用以下两种方法调试：

一、Debug视图

 1、Junit下的

发现配置事务的AOP已经包进来了。再看看Tomcat中运行的Debug截图：

显然AOP没有被包进来。

二、Log4J的记录：

Junit下的记录：

Spring托管了事务。

Tomcat运行时的记录：

Spring没有托管事务。

从以上两种方法的调试说明了，事务的配置是正确的，只是在部署到Tomcat中，没有被托管。为什么会在Junit的时候就可以呢？得看看Junit的配置：

@RunWith(SpringJUnit4ClassRunner.class)
@TestExecutionListeners({DependencyInjectionTestExecutionListener.class})
@ContextConfiguration("classpath:applicationContext.xml")

这是Junit加载Spring容器的注解。ContextConfiguration会把applicationContext.xml的Bean都加载了，这就说明Tomcat在运行时没有将applicationContext.xml的Bean加载进来。问了前辈，前辈的回话是这样的：

切面配置在了root applicationContext的bean上了，而spring mvc会根据xxx-servelt.xml生成一个自己的applicationContext，他的父applicationContext为root applicatonContext，当mvc有自己的bean时便不再去向父context要bean，导致声明事务无效。

看了前辈的这个邮件，我将applicationContext.xml中配置事务的AOP复制到XXX-servlet.xml中。再调试，Tomcat中运行项目事务被Spring托管了，也就是问题解决了！！

问题解决后查看了Spring3.1的Docs发现了以下的内容：

These inherited beans can be overridden in the servlet-specific scope, and you can define new scope-specific beans local to a given Servlet instance.
Context hierarchy in Spring Web MVC Upon initialization of a DispatcherServlet, Spring MVC looks for a file named [servlet-name]-servlet.xml in the WEB-INF directory of your web application and creates the beans defined there, overriding the definitions of any beans defined with the same name in the global scope.