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采用AOP配置声明式事务有5种方式,下面只说关于采用TransactionInterceptor事务拦截器的方式,配置程序如下:
transactionManager:
- <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close" />
-
- <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
- <property name="dataSource" ref="dataSource" />
- </bean>
TransactionInterceptor:
- <bean id="transactionInterceptor" class="org.springframework.transaction.interceptor.TransactionInterceptor">
- <property name="transactionManager" ref="transactionManager" />
- <property name="transactionAttributes">
- <props>
- <prop key="add*">PROPAGATION_REQUIRED</prop>
- <prop key="del*">PROPAGATION_REQUIRED</prop>
- <prop key="update*">PROPAGATION_REQUIRED</prop>
- <prop key="query*">readOnly</prop>
- <prop key="get*">readOnly</prop>
- <prop key="find*">readOnly</prop>
- <prop key="check*">PROPAGATION_REQUIRED</prop>
- <prop key="operate*">PROPAGATION_REQUIRED</prop>
- <prop key="batch*">PROPAGATION_REQUIRED</prop>
- <prop key="deploy*">PROPAGATION_REQUIRED</prop>
- <prop key="exec*">PROPAGATION_REQUIRED</prop>
- </props>
- </property>
- </bean>
自动代理BeanNameAutoProxyCreator:
- <bean class="org.springframework.aop.framework.autoproxy.BeanNameAutoProxyCreator">
- <property name="beanNames">
- <!-- 所有以BUSImpl命名的Bean-Id都会被事务拦截-->
- <value>*BUSImpl</value>
- </property>
- <property name="interceptorNames">
- <list>
- <value>transactionInterceptor</value>
- </list>
- </property>
- </bean>
业务类例子:
- public class UserManageBUSImpl implements IBusiness{
- private UserDAO dao;
- public void addUser(User user) throws Exception{
- dao.save(user);
- }
- }
- public class UserDAO implements IDAO{
- private JdbcTemplate db;
- public void save(User user) throws Exception{
- db.update("insert into User(...) values(...)");
- throw new Exception("test exception"); // 这里我们故意抛出异常作为测试
- }
- }
然后运行发现记录仍然保存进去了,事务失效;
why?
我们首先应该知道使用事务回滚和提交,归根结底是在JDBC里完成的,这里声明事务拦截器仅是为JDK代理切入点拦截。而做事务提交和回滚是transactionManager完成的事。那么断点跟进拦截器里程序发现:
- public Object invoke(final MethodInvocation invocation) throws Throwable {
- // Work out the target class: may be <code>null</code>.
- // The TransactionAttributeSource should be passed the target class
- // as well as the method, which may be from an interface.
- Class targetClass = (invocation.getThis() != null ? invocation.getThis().getClass() : null);
-
- // If the transaction attribute is null, the method is non-transactional.
- final TransactionAttribute txAttr =
- getTransactionAttributeSource().getTransactionAttribute(invocation.getMethod(), targetClass);
- final String joinpointIdentification = methodIdentification(invocation.getMethod());
-
- if (txAttr == null || !(getTransactionManager() instanceof CallbackPreferringPlatformTransactionManager)) {
- // Standard transaction demarcation with getTransaction and commit/rollback calls.
- TransactionInfo txInfo = createTransactionIfNecessary(txAttr, joinpointIdentification);
- Object retVal = null;
- try {
- // This is an around advice: Invoke the next interceptor in the chain.
- // This will normally result in a target object being invoked.
- retVal = invocation.proceed();
- }
- catch (Throwable ex) {
- // target invocation exception
- <SPAN style="COLOR: #000000">completeTransactionAfterThrowing(txInfo, ex);</SPAN>
- throw ex;
- }
- finally {
- cleanupTransactionInfo(txInfo);
- }
- commitTransactionAfterReturning(txInfo);
- return retVal;
- }
- ......
completeTransactionAfterThrowing(txInfo, ex);这句话是异常捕获后做的事情,那么再跟进发现:
- protected void completeTransactionAfterThrowing(TransactionInfo txInfo, Throwable ex) {
- if (txInfo != null && txInfo.hasTransaction()) {
- if (logger.isDebugEnabled()) {
- logger.debug("Completing transaction for [" + txInfo.getJoinpointIdentification() + "] after exception: " + ex);
- }
- <SPAN style="COLOR: #ff0000">if (txInfo.transactionAttribute.rollbackOn(ex)) { // 需满足这个条件</SPAN>
- try {
- <SPAN style="COLOR: #ff0000">this.transactionManager.rollback(txInfo.getTransactionStatus()); // 这里才完成JDBC事务回滚</SPAN>
- } 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; }
- }
- ......
看来离真相越来越接近了,txInfo.transactionAttribute是什么呢?查看源码对应到一个接口TransactionAttribute,文档如下:
-
- public interface TransactionAttribute extends TransactionDefinition {
-
-
- boolean rollbackOn(Throwable ex);
-
- }
看下RuleBasedTransactionAttribute里实现的接口方法:
- public boolean rollbackOn(Throwable ex) {
- if (logger.isDebugEnabled()) {
- logger.debug("Applying rules to determine whether transaction should rollback on " + ex);
- }
- RollbackRuleAttribute winner = null;
- int deepest = Integer.MAX_VALUE;
- if (this.rollbackRules != null) {
- <SPAN style="COLOR: #ff0000">// 看来这里是要满足自定义回滚规则
- for (Iterator it = this.rollbackRules.iterator(); it.hasNext();) {
- </SPAN> RollbackRuleAttribute rule = (RollbackRuleAttribute) it.next();
- int depth = rule.getDepth(ex);
- if (depth >= 0 && depth < deepest) {
- deepest = depth; winner = rule;
- }
- }
- }
- if (logger.isDebugEnabled()) {
- logger.debug("Winning rollback rule is: " + winner);
- }
- // User superclass behavior (rollback on unchecked) if no rule matches.
- if (winner == null) {
- logger.debug("No relevant rollback rule found: applying superclass default");
- <SPAN style="COLOR: #ff0000">return super.rollbackOn(ex); // 如果没有规则,则调用父类方法验证回滚规则</SPAN>
- }
- return !(winner instanceof NoRollbackRuleAttribute); }
其父类方法为:
-
- public boolean rollbackOn(Throwable ex) {
- <SPAN style="COLOR: #ff0000"><SPAN style="COLOR: #000000"> </SPAN>return (ex instanceof RuntimeException || ex instanceof Error); // 最终是这个原因</SPAN>
- }
原因:
由于业务类里抛出的异常不满足事务拦截器里定义的异常(RuntimeException|Error)事务回滚规则,故事务无效;
解决方案:
1,将业务类的抛出异常改为满足拦截器里的异常规则(不推荐,因为要修改以前所有的代码)
2,(推荐方案)在事务拦截器里声明自定义回滚规则,即this.rollbackRules.iterator()中有你自己申明的异常类,这个方案仅需在spring中配置如下:
- <bean id="transactionInterceptor" class="org.springframework.transaction.interceptor.TransactionInterceptor">
- <property name="transactionManager" ref="transactionManager" />
- <property name="transactionAttributes">
- <props>
- <prop key="add*">PROPAGATION_REQUIRED, -Exception</prop>
- <prop key="del*">PROPAGATION_REQUIRED, -Exception</prop>
- <prop key="update*">PROPAGATION_REQUIRED, -Exception</prop>
- <prop key="query*">readOnly</prop>
- <prop key="get*">readOnly</prop>
- <prop key="find*">readOnly</prop>
- <prop key="check*">PROPAGATION_REQUIRED, -Exception</prop>
- <prop key="operate*">PROPAGATION_REQUIRED, -Exception</prop>
- <prop key="batch*">PROPAGATION_REQUIRED, -Exception</prop>
- <prop key="deploy*">PROPAGATION_REQUIRED, -Exception</prop>
- <prop key="exec*">PROPAGATION_REQUIRED, -Exception</prop>
- </props>
- </property>
- </bean>
转载地址:http://blog.sina.com.cn/s/blog_56fd58ab0100gjhv.html