Spring事務異常rollback-only

轉自:https://blog.csdn.net/sgls652709/article/details/49472719

 

前言

在利用單元測試驗證spring事務傳播機制的時候出現了下面的異常： 
Transaction rolled back because it has been marked as rollback-only。記錄問題解決的步驟

正文

代碼示例

代碼-測試單元

@RunWith(SpringJUnit4ClassRunner.class) @ContextConfiguration("classpath:config/spring-config-test.xml") @TransactionConfiguration(transactionManager="transactionManager",defaultRollback=false) @Transactional public class RegisterServiceTest { @Resource(name="registerService") private IRegisterService service; @Test public void registerTest() { RegisterDTO dto = new RegisterDTO(); dto.setDisplayname("superman12345"); dto.setPassword("99999"); service.register(dto); } }

代碼-RegisterService

@Transactional @Service public class RegisterService implements IRegisterService { @Resource private ILogonService logonService; @Resource private IUserService userService; @Override @Transactional(propagation=Propagation.REQUIRED) public void register(RegisterDTO dto) { try{ logonService.addLogon(dto); }catch(Exception e) { } userService.addUser(dto); } }

 

代碼-LogonService

@Transactional @Service public class LogonService implements ILogonService { @Resource(name="logonDaoImpl") private LogonDAO logonDao; @Override @Transactional(propagation=Propagation.REQUIRED) public int addLogon(RegisterDTO dto) { //注冊登錄信息 logonDao.addLogon(dto); throw new RuntimeException(); } }

 

代碼-UserService

@Transactional @Service public class UserService implements IUserService { @Resource(name="userDaoImpl") private UserDAO userDao; @Override @Transactional(propagation=Propagation.REQUIRED) public int addUser(RegisterDTO dto) { // 是否存在用戶 if (userDao.findUser(dto) != null) { throw new RuntimeException("已經存在用戶"); } // 注冊用戶,使用jdbcTempalte插入用戶信息 int userid = userDao.addUser(dto); dto.setUserid(userid); return userid; } }

 

 

背景說明：

一、從上面的代碼看出，我是采用注解來定義與注入spring元數據的，spring在web.xml文件的監聽函數ContextLoaderListener，創建applicationContext，在AbstractApplicationContext的refresh中，加載元數據，裝配元數據以及初始化元數據，對於service層的類，符合事務切面中的切點的匹配，那么在初始化這些service對象的時候采用的是代理創建，所以在Ioc容器（BeanFactory提供緩存元數據信息的集合）中，我們緩存的這些service對象就是代理對象。執行logonService.addLogon，userService.addUser的時候，我們執行代理對象的方法，其中事務攔截器TransactionInterceptor便是tx:advice提供的增強，通過代理織入到我們的業務代碼中 
二、事務傳播機制的實現原理，如果幾個不同的service都是共享同一個connect（也就是service對象嵌套傳播機制為Propagation.REQUIRED），jdbc的connect.commit、connect.rollback，一起提交，一起回滾。這里面共享conntion應該就是共享同一個事務了。不同的connect,來執行commit/rollback自然是獨立的。同一個connection，如果一個service已經提交了，在另外service中connect.rollback自然對第一個service提交的代碼回滾不了的。所以spring處理且套事務，就是在TransactionInterceptor方法中，根據一系列開關（Propagation枚舉中的屬性），來處理connetion事務是同一個還是重新獲取，如果是同一個connection,不同service的commit(注：①)與rollback（注：②）的時機

注①：執行某一個service的時候根據傳播機制例如REQUIRED，spring發現事務沒建立，建立事務，在status對象中標記newTransaction為true,嵌套事務還有一個service是REQUIRED，那么使用這個事務，它的status中newTransaction為false，如果newTransaction為false的時候，commit全部跳過，如果是true，那么說明這個service是事務outermost transaction boundary，開始提交 
注②：如果newTransaction為false，那么標記為rollback-only，如果是true，那么執行rollback

代碼調試

執行的時候發現出現了下面的異常

org.springframework.transaction.UnexpectedRollbackException: Transaction rolled back because it has been marked as rollback-only at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:720) at org.springframework.test.context.transaction.TransactionalTestExecutionListener$TransactionContext.endTransaction(TransactionalTestExecutionListener.java:597) at org.springframework.test.context.transaction.TransactionalTestExecutionListener.endTransaction(TransactionalTestExecutionListener.java:296) at org.springframework.test.context.transaction.TransactionalTestExecutionListener.afterTestMethod(TransactionalTestExecutionListener.java:189) at org.springframework.test.context.TestContextManager.afterTestMethod(TestContextManager.java:404) at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:91) at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:232) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:89) at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290) at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71) at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288) at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58) at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268) at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61) at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71) at org.junit.runners.ParentRunner.run(ParentRunner.java:363) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:175) at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86) at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192) 

 

根據上面出錯異常定位到異常信息的720行，報錯代碼satus.isNewTransaction為true

if (status.isNewTransaction() || isFailEarlyOnGlobalRollbackOnly()) { throw new UnexpectedRollbackException( "Transaction rolled back because it has been marked as rollback-only"); }

 

這段代碼的意思是：共享的事物中已經有service出錯了，已經標記成rollback-only了，這里isNewTransaction是true，那么說明你是到了事物最外層的service了，你就不應該commit，應該rollback的。但是我想知道為什么會執行commit而不是rollback

定位異常報錯第597行，下面的代碼是spring-test中的源碼

public void endTransaction(boolean rollback) { if (rollback) { this.transactionManager.rollback(this.transactionStatus); } else { this.transactionManager.commit(this.transactionStatus); } }

 

原來這里由rollback控制，我繼續向上定位，看rollback是如何獲取的

定位代碼296行

private void endTransaction(TestContext testContext, TransactionContext txContext) throws Exception { boolean rollback = isRollback(testContext); if (logger.isTraceEnabled()) { logger.trace(String.format( "Ending transaction for test context %s; transaction status [%s]; rollback [%s]", testContext, txContext.transactionStatus, rollback)); } txContext.endTransaction(rollback); if (logger.isInfoEnabled()) { logger.info((rollback ? "Rolled back" : "Committed") + " transaction after test execution for test context " + testContext); } }

 

在boolean rollback = isRollback(testContext);獲取rollback,進入代碼，最后發現由成員屬性defaultRollback來控制，這個defaultRollback就是上面我配置的

@TransactionConfiguration(transactionManager="transactionManager",defaultRollback=false) 

 

這里我設置成了defaultRollback為false，說到這行代碼我單元測試也剛剛掌握點皮毛，我發現只要有@Transactional就可以自動回滾測試代碼，不論成功與否。好吧，看到上面代碼新奇，用上了，控制默認不會滾，碰到錯誤也強制提交，okey,碰到事務嵌套，如果共享事物中某個service出現錯誤(注：③)，那么強制提交也錯了

注③：spring事務源碼，對runtimeException和error的異常會捕獲處理回滾，但是檢查異常代碼，不會捕獲，直接提交，這樣也會導致rollback-only這樣的異常，當然，像我上面代碼service層直接try catch掉嵌套事務中，某一個service異常，在共享事物的時候，外層捕獲不到異常，直接commit，也是會出現rollback-only這樣的異常的，這在下面我會分析

代碼修改

上面測試代碼defaultRollback設置成true。將共享事務最開始（newTransaction為true）設在RegisterService中，它的事務傳播機制改成

@Transactional(propagation=Propagation.REQUIRES_NEW) public void register(RegisterDTO dto) { try{ logonService.addLogon(dto); }catch(Exception e) { } userService.addUser(dto); }

 

分析一下這里執行的過程：單元測試創建了一個事務，調用register，發現傳播機制是REQUIRES_NEW，那么掛起原來的事物，重新新建事務，logonService方法與userService方法是Propagation.REQUIRED，所以會共享這個新建的事物，register這里是它們

代碼-異常信息

org.springframework.transaction.UnexpectedRollbackException: Transaction rolled back because it has been marked as rollback-only at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:720) at org.springframework.transaction.interceptor.TransactionAspectSupport.commitTransactionAfterReturning(TransactionAspectSupport.java:478) at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:272) at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:95) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:207) at com.sun.proxy.$Proxy25.register(Unknown Source) at org.test.service.RegisterServiceTest.registerTest(RegisterServiceTest.java:28) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:497) at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47) at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17) at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:74) at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:83) at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:232) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:89) at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290) at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71) at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288) at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58) at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268) at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61) at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71) at org.junit.runners.ParentRunner.run(ParentRunner.java:363) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:175) at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86) at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)

 

這里原因還是和上面一樣outermost transaction boundary執行commit，應該是rollback

定位720行代碼

// Throw UnexpectedRollbackException only at outermost transaction boundary // or if explicitly asked to. if (status.isNewTransaction() || isFailEarlyOnGlobalRollbackOnly()) { throw new UnexpectedRollbackException( "Transaction rolled back because it has been marked as rollback-only"); }

 

這里是出錯的位置，我們一層一層定位上去，找到了下面的代碼

if (txAttr == null || !(tm instanceof CallbackPreferringPlatformTransactionManager)) { // Standard transaction demarcation with getTransaction and commit/rollback calls. TransactionInfo txInfo = createTransactionIfNecessary(tm, 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.proceedWithInvocation(); } catch (Throwable ex) { // target invocation exception completeTransactionAfterThrowing(txInfo, ex); throw ex; } finally { cleanupTransactionInfo(txInfo); } commitTransactionAfterReturning(txInfo); return retVal; }

 

這里執行了commitTransactionAfterReturning而不是completeTransactionAfterThrowing(txInfo, ex); 這很明顯，是因為沒有捕獲異常，導致的原因是我try-catch掉了。沒辦法，去掉try-catch，或者拋異常的logonService傳播機制改為propagation=Propagation.REQUIRES_NEW，讓它自己獨自提交回滾，別再設置rollback-only這種全局的標識來惡心。

看看spring事務能什么樣的異常能捕獲並回滾，什么異常不捕獲，直接提交。上面的代碼completeTransactionAfterThrowing,進去以后會發現有一個if else邏輯，其中條件判斷為

txInfo.transactionAttribute.rollbackOn(ex)

進去以后我找到了下面的代碼

public boolean rollbackOn(Throwable ex) { return (ex instanceof RuntimeException || ex instanceof Error); }

 

看樣子，spring默認只對RuntimeException和Error做捕捉，並回滾，其他的異常，直接提交

最后談談自己讀源碼的一些經驗。 
1、最好還是從異常報錯信息中一步一步定位去了解為什么出現這樣的錯誤 
2、實在處於興趣想讀源碼，那么使用eclipse提供的工具如call Hierarchy,點擊某個方法，直接右鍵，可以找到，或者使用默認快捷鍵ctrl+alt+h。這個工具提供了方法調用、與被調用的樹層次結構，在上面點點，一步一步下去，可以點某個方法立即定位之前的代碼 
3、debug，這個必須要用吧，不然，那么復雜的類層次結構，沒有指南針怎么行 
4、主要還是理解里面處理的思想，實現的話還是不要太過於糾結，先理清思路，明白具體做什么的。在慢慢深入，有值得借鑒的地方，去模仿 
5、花時間、慢慢啃，每次總會有收獲的