解决org.springframework.transaction.UnexpectedRollbackException: Transaction silently rolled back beca

文章目录

• 1. 复现错误
• 2. 分析错误
• 3. 分析spring的事务机制
• • 3.1 入口程序
  • 3.2 事务管理的主方法
  • 3.3 细究各对象的获取
• 4. functionTwo方法抛异常后的回滚操作
• 5. functionOne方法尝试提交时的操作
• 6. 总结

1. 复现错误

今天本地使用Knife4j调用后端接口时，报出如下图的错误：

于是，查看后端控制台的输出结果，如下所示：

org.springframework.transaction.UnexpectedRollbackException: Transaction silently rolled back because it has been marked as rollback-onlyat org.springframework.transaction.support.AbstractPlatfORMTransactionManager.processCommit(AbstractPlatformTransactionManager.java:752)at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:711)at org.springframework.transaction.interceptor.TransactionAspectSupport.commitTransactionAfterReturning(TransactionAspectSupport.java:654)at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:407)at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:119)at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:750)at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:692)at com.test.cloud.service.ModelService$$EnhancerBySprinGCGLIB$$a05f18b.generatePage(<generated>)at com.test.cloud.controller.ModelController.generatePage(ModelController.java:169)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:498)at org.springframework.WEB.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:197)at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:141)at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:106)at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:894)at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808)at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1063)at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:963)at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006)at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:909)at javax.servlet.Http.httpservlet.service(HttpServlet.java:652)at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)at javax.servlet.http.HttpServlet.service(HttpServlet.java:733)at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227)at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)at org.apache.Tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)......

即Transaction silently rolled back because it has been marked as rollback-only

之前也遇到这个错误，但由于不太懂事务的嵌套，且总不能重现这个错误。

趁着此次的错误，彻底研究该错误形成的原因。

2. 分析错误

将Transaction silently rolled back because it has been marked as rollback-only翻译成中文，即事务以静默方式回滚，因为它已被标记为仅回滚。

那么，这句话是什么意思呢？通过对以下代码的分析，来了解它的含义。

因为公司代码不能泄露，特写如下三个测试类:

1. CommonApplicationTests：Spring Boot自带的测试类

@SpringBootTestclass CommonApplicationTests {  @Autowired  TestRollbackService testRollbackService;  public void testRollback(){    try{      testRollbackService.functionOne();    }catch(Exception e){      e.printStackTrace();    }  }}

2. TestRollbackService：事务回滚类

@Autowiredprivate UserMapper userMapper;@Autowiredprivate TestTransactionService testTransactionService;@Transactional(rollbackFor = BizException.class)public void functionOne(){try{      User updateUser = new User();    updateUser.setId(new Long(19));    updateUser.setName("super先生");    userMapper.updateByPrimaryKey(updateUser);        testTransactionService.functionTwo();    }catch(Exception e){        e.printStackTrace();    }}

3. TestTransactionService：事务执行类

@Autowiredprivate AddreSSMapper addressMapper; @Transactional(rollbackFor = BizException.class)public void functionTwo(){  Address addressUpdate=new Address();  addressUpdate.setId(1L);  addressUpdate.setDetail("无锡市经开区")  addressMapper.updateByPrimaryKey(addressUpdate);  System.out.println(1/0);}

如上两个方法，分别为functionOne和functionTwo。

functionOne加上了 @Transactional(rollbackFor = BizException.class)。

与此同时，functionTwo也加上了 @Transactional(rollbackFor = BizException.class)。

你在functionOne中调用了functionTwo，而functionTwo报出了错误信息，即可触发回滚异常的报错。

两个方法都加了事务注解，它们都会受到到事务管理的拦截器增强，并且事务传播的方式都是默认的，也就是REQUIRED，当已经存在事务的时候就加入事务，没有就创建事务。

这里functionOne和functionTwo都受事务控制，并且是处于同一个事务的。

functionOne调用了functionTwo，functionOne中抓了functionTwo的异常。当functionTwo发生异常时，functionTwo的操作应该回滚。

但functionOne吃了异常，functionOne方法中没有产生异常，所以functionOne的操作又应该提交，二者是相互矛盾的。

spring的事务关联拦截器在抓到functionTwo的异常后，就会标记rollback-only为true。当functionOne执行完准备提交后，发现rollback-only为true，也会回滚，并抛出异常告诉调用者。

程序时序图如下:

3. 分析spring的事务机制

3.1 入口程序

程序入口走cglib的代理类(CglibAopProxy)。

找到CglibAopProxy的DynamicAdvisedInterceptor.class内部类，可以看到入口方法(intercept)如下：

@Nullablepublic Object intercept(Object proxy, Method method, Object[] args, MethodProxy methodProxy) throws Throwable {    Object oldProxy = null;    boolean setProxyContext = false;    Object target = null;    TargetSource targetSource = this.advised.getTargetSource();    Object var16;    .....}

在该方法(intercept)中的找到如下语句：

即语句retVal = (new CglibAopProxy.CglibMethodInvocation(proxy, target, method, args, targetClass, chain, methodProxy)).proceed();

点击上图中CglibMethodInvocation类，即可到CglibAopProxy的CglibMethodInvocation内部类的如下方法：

然后找到TransactionInterceptor类，即到了事务管理的拦截器，如下图所示：

3.2 事务管理的主方法

invokeWithinTransaction是事务管理的主方法。

@Nullableprotected Object invokeWithinTransaction(Method method, @Nullable Class<?> targetClass, TransactionAspectSupport.InvocationCallback invocation) throws Throwable {    TransactionAttributeSource tas = this.getTransactionAttributeSource();    TransactionAttribute txAttr = tas != null ? tas.getTransactionAttribute(method, targetClass) : null;    TransactionManager tm = this.determineTransactionManager(txAttr);    if (this.ReactiveAdapterReGIStry != null && tm instanceof ReactiveTransactionManager) {        boolean isSuspendingFunction = KotlinDetector.isSuspendingFunction(method);        boolean hasSuspendingFlowReturnType = isSuspendingFunction && "kotlinx.coroutines.flow.Flow".equals((new MethodParameter(method, -1)).getParameterType().getName());        if (isSuspendingFunction && !(invocation instanceof TransactionAspectSupport.CoroutinesInvocationCallback)) {            throw new IllegalStateException("Coroutines invocation not supported: " + method);        } else {            TransactionAspectSupport.CoroutinesInvocationCallback corInv = isSuspendingFunction ? (TransactionAspectSupport.CoroutinesInvocationCallback)invocation : null;            TransactionAspectSupport.ReactiveTransactionSupport txSupport = (TransactionAspectSupport.ReactiveTransactionSupport)this.transactionSupportCache.computeIfAbsent(method, (key) -> {                Class<?> reactiveType = isSuspendingFunction ? (hasSuspendingFlowReturnType ? Flux.class : Mono.class) : method.getReturnType();                ReactiveAdapter adapter = this.reactiveAdapterRegistry.getAdapter(reactiveType);                if (adapter == null) {                    throw new IllegalStateException("Cannot apply reactive transaction to non-reactive return type: " + method.getReturnType());                } else {                    return new TransactionAspectSupport.ReactiveTransactionSupport(adapter);                }            });            TransactionAspectSupport.InvocationCallback callback = invocation;            if (corInv != null) {                callback = () -> {                    return CoroutinesUtils.invokeSuspendingFunction(method, corInv.getTarget(), corInv.getArguments());                };            }            Object result = txSupport.invokeWithinTransaction(method, targetClass, callback, txAttr, (ReactiveTransactionManager)tm);            if (corInv != null) {                Publisher<?> pr = (Publisher)result;                return hasSuspendingFlowReturnType ? TransactionAspectSupport.KotlinDelegate.asFlow(pr) : TransactionAspectSupport.KotlinDelegate.awaitSingleOrNull(pr, corInv.getContinuation());            } else {                return result;            }        }    } else {        PlatformTransactionManager ptm = this.asPlatformTransactionManager(tm);        String joinpointIdentification = this.methodIdentification(method, targetClass, txAttr);        if (txAttr != null && ptm instanceof CallbackPreferringPlatformTransactionManager) {            TransactionAspectSupport.ThrowableHolder throwableHolder = new TransactionAspectSupport.ThrowableHolder();            Object result;            try {                result = ((CallbackPreferringPlatformTransactionManager)ptm).execute(txAttr, (statusx) -> {                    TransactionAspectSupport.TransactionInfo txInfo = this.prepareTransactionInfo(ptm, txAttr, joinpointIdentification, statusx);                    Object var9;                    try {                        Object retVal = invocation.proceedWithInvocation();                        if (retVal != null && vavrPresent && TransactionAspectSupport.VavrDelegate.isVavrTry(retVal)) {retVal = TransactionAspectSupport.VavrDelegate.evaluateTryFailure(retVal, txAttr, statusx);                        }                        var9 = retVal;                        return var9;                    } catch (Throwable var13) {                        if (txAttr.rollbackOn(var13)) {if (var13 instanceof RuntimeException) {    throw (RuntimeException)var13;}throw new TransactionAspectSupport.ThrowableHolderException(var13);                        }                        throwableHolder.throwable = var13;                        var9 = null;                    } finally {                        this.cleanupTransactionInfo(txInfo);                    }                    return var9;                });            } catch (TransactionAspectSupport.ThrowableHolderException var22) {                throw var22.getCause();            } catch (TransactionSystemException var23) {                if (throwableHolder.throwable != null) {                    this.logger.error("Application exception overridden by commit exception", throwableHolder.throwable);                    var23.initApplicationException(throwableHolder.throwable);                }                throw var23;            } catch (Throwable var24) {                if (throwableHolder.throwable != null) {                    this.logger.error("Application exception overridden by commit exception", throwableHolder.throwable);                }                throw var24;            }            if (throwableHolder.throwable != null) {                throw throwableHolder.throwable;            } else {                return result;            }        } else {            TransactionAspectSupport.TransactionInfo txInfo = this.createTransactionIfNecessary(ptm, txAttr, joinpointIdentification);            Object retVal;            try {                retVal = invocation.proceedWithInvocation();            } catch (Throwable var20) {                this.completeTransactionAfterThrowing(txInfo, var20);                throw var20;            } finally {                this.cleanupTransactionInfo(txInfo);            }            if (retVal != null && vavrPresent && TransactionAspectSupport.VavrDelegate.isVavrTry(retVal)) {                TransactionStatus status = txInfo.getTransactionStatus();                if (status != null && txAttr != null) {                    retVal = TransactionAspectSupport.VavrDelegate.evaluateTryFailure(retVal, txAttr, status);                }            }            this.commitTransactionAfterReturning(txInfo);            return retVal;        }    }}

程序执行的是else分支，步骤很清晰

1. 获取TransactionAttribute

2. 基于TransactionAttribute获取TransactionManager

3. 基于TransactionAttribute获取joinpointIdentification(没研究什么作用)

4. 基于1,2,3创建的对象获取 TransactionAspectSupport.TransactionInfo。transactionInfo是TransactionAspectSupport的一个内部类

5. 执行业务方法

6. 抓到异常就回滚，并清除事务，然后向上抛异常；没有异常就清除事务，然后提交。

对象之间的关联关系如下图所示：

3.3 细究各对象的获取

TransactionManager的获取比较简单，程序里获取到的其实就是自己配置的bean。

创建TransactionInfo的过程中要先获取TransactionStatus。

TransactionStatus又需要拿到ConnectionHolder。

1. createTransactionIfNecessary

createTransactionIfNecessary方法在类TransactionAspectSupport中。

protected TransactionAspectSupport.TransactionInfo createTransactionIfNecessary(@Nullable PlatformTransactionManager tm, @Nullable TransactionAttribute txAttr, final String joinpointIdentification) {    if (txAttr != null && ((TransactionAttribute)txAttr).getName() == null) {        txAttr = new DelegatingTransactionAttribute((TransactionAttribute)txAttr) {            public String getName() {                return joinpointIdentification;            }        };    }    TransactionStatus status = null;    if (txAttr != null) {        if (tm != null) {            status = tm.getTransaction((TransactionDefinition)txAttr);        } else if (this.logger.isDebugEnabled()) {            this.logger.debug("Skipping transactional joinpoint [" + joinpointIdentification + "] because no transaction manager has been configured");        }    }    return this.prepareTransactionInfo(tm, (TransactionAttribute)txAttr, joinpointIdentification, status);}

2. 获取TransactionStatus

这里通过status = tm.getTransaction((TransactionDefinition)txAttr)语句来创建TransactionStatus。

接着看语句中的getTransaction方法，它在在类AbstractPlatformTransactionManager中，如下所示：

public final TransactionStatus getTransaction(@Nullable TransactionDefinition definition) throws TransactionException {    Object transaction = this.doGetTransaction();    boolean debugEnabled = this.logger.isDebugEnabled();    if (definition == null) {        definition = new DefaultTransactionDefinition();    }    if (this.isExistingTransaction(transaction)) {        return this.handleExistingTransaction((TransactionDefinition)definition, transaction, debugEnabled);    } else if (((TransactionDefinition)definition).getTimeout() < -1) {        throw new InvalidTimeoutException("Invalid transaction timeout", ((TransactionDefinition)definition).getTimeout());    } else if (((TransactionDefinition)definition).getPropagationBehavior() == 2) {        throw new IllegalTransactionStateException("No existing transaction found for transaction marked with propagation 'mandatory'");    } else if (((TransactionDefinition)definition).getPropagationBehavior() != 0 && ((TransactionDefinition)definition).getPropagationBehavior() != 3 && ((TransactionDefinition)definition).getPropagationBehavior() != 6) {        if (((TransactionDefinition)definition).getIsolationLevel() != -1 && this.logger.isWarnEnabled()) {            this.logger.warn("Custom isolation level specified but no actual transaction initiated; isolation level will effectively be ignored: " + definition);        }        boolean newSynchronization = this.getTransactionSynchronization() == 0;        return this.prepareTransactionStatus((TransactionDefinition)definition, (Object)null, true, newSynchronization, debugEnabled, (Object)null);    } else {        AbstractPlatformTransactionManager.SuspendedResourcesHolder suspendedResources = this.suspend((Object)null);        if (debugEnabled) {            this.logger.debug("Creating new transaction with name [" + ((TransactionDefinition)definition).getName() + "]: " + definition);        }        try {            boolean newSynchronization = this.getTransactionSynchronization() != 2;            DefaultTransactionStatus status = this.newTransactionStatus((TransactionDefinition)definition, transaction, true, newSynchronization, debugEnabled, suspendedResources);            this.doBegin(transaction, (TransactionDefinition)definition);            this.prepareSynchronization(status, (TransactionDefinition)definition);            return status;        } catch (Error | RuntimeException var7) {            this.resume((Object)null, suspendedResources);            throw var7;        }    }}

3. 获取transactionStatus前先获取DataSourceTransactionObject

通过程序最上面的语句 Object transaction = this.doGetTransaction();来创建DataSourceTransactionObject对象，这是DataSourceTransactionManager的内部类

我们来看语句中的doGetTransaction方法，它在类DataSourceTransactionManager中，如下代码所示：

protected Object doGetTransaction() {   DataSourceTransactionManager.DataSourceTransactionObject txObject = new DataSourceTransactionManager.DataSourceTransactionObject();   txObject.setSavepointAllowed(this.isNestedTransactionAllowed());   ConnectionHolder conHolder = (ConnectionHolder)TransactionSynchronizationManager.getResource(this.obtainDataSource());   txObject.setConnectionHolder(conHolder, false);   return txObject;}

同时，这里获取了ConnectionHolder对象，此处的newConnectionHolder为false

接着看doGetTransaction方法中的TransactionSynchronizationManager.getResource方法，如下代码所示：

@Nullablepublic static Object getResource(Object key) {    Object actualKey = TransactionSynchronizationUtils.unwrapResourceIfNecessary(key);    Object value = doGetResource(actualKey);    if (value != null && logger.isTraceEnabled()) {        logger.trace("Retrieved value [" + value + "] for key [" + actualKey + "] bound to thread [" + Thread.currentThread().getName() + "]");    }    return value;}

通过一个key获取的，类似于从一个池子里面拿东西一样。

其实当functionOne方法执行时，并没有获取到ConnectionHolder，拿到的是null。

我们继续看getResource方法中的doGetResource方法。

doGetResource方法是在类TransactionSynchronizationManager中。

private static Object doGetResource(Object actualKey) {    Map<Object, Object> map = (Map)resources.get();    if (map == null) {        return null;    } else {        Object value = map.get(actualKey);        if (value instanceof ResourceHolder && ((ResourceHolder)value).isVoid()) {            map.remove(actualKey);            if (map.isEmpty()) {                resources.remove();            }             value = null;        }         return value;    }}

resources对象其实是一个ThreadLocal，意思是同一个线程中拿到的ConnectionHolder是相同的。

4. doBegin方法

doBegin方法是在类DataSourceTransactionManager中。

protected void doBegin(Object transaction, TransactionDefinition definition) {    DataSourceTransactionManager.DataSourceTransactionObject txObject = (DataSourceTransactionManager.DataSourceTransactionObject)transaction;    Connection con = null;     try {        if (!txObject.hasConnectionHolder() || txObject.getConnectionHolder().isSynchronizedWithTransaction()) {            Connection newCon = this.obtainDataSource().getConnection();            if (this.logger.isDebugEnabled()) {                this.logger.debug("Acquired Connection [" + newCon + "] for JDBC transaction");            }             txObject.setConnectionHolder(new ConnectionHolder(newCon), true);        }         txObject.getConnectionHolder().setSynchronizedWithTransaction(true);        con = txObject.getConnectionHolder().getConnection();        Integer previousIsolationLevel = DataSourceUtils.prepareConnectionForTransaction(con, definition);        txObject.setPreviousIsolationLevel(previousIsolationLevel);        if (con.getAutoCommit()) {            txObject.setMustRestoreAutoCommit(true);            if (this.logger.isDebugEnabled()) {                this.logger.debug("Switching JDBC Connection [" + con + "] to manual commit");            }             con.setAutoCommit(false);        }         this.prepareTransactionalConnection(con, definition);        txObject.getConnectionHolder().setTransactionActive(true);        int timeout = this.determineTimeout(definition);        if (timeout != -1) {            txObject.getConnectionHolder().setTimeoutInSeconds(timeout);        }         if (txObject.isNewConnectionHolder()) {            TransactionSynchronizationManager.bindResource(this.obtainDataSource(), txObject.getConnectionHolder());        }     } catch (Throwable var7) {        if (txObject.isNewConnectionHolder()) {            DataSourceUtils.releaseConnection(con, this.obtainDataSource());            txObject.setConnectionHolder((ConnectionHolder)null, false);        }         throw new CannotCreateTransactionException("Could not open JDBC Connection for transaction", var7);    }}

截取该方法的重要几行:

Connection newCon = this.obtainDataSource().getConnection();if (this.logger.isDebugEnabled()) {    this.logger.debug("Acquired Connection [" + newCon + "] for JDBC transaction");} txObject.setConnectionHolder(new ConnectionHolder(newCon), true);

先获取连接(java.sql.Connection)，接着创建ConnectionHolder。

newConnectionHolder设置为true，如果之前不为空，newConnectionHolder则为false。

如果newConnectionHolder为true，还需要将connectionHolder放到threadLocal里面，让后面的方法可以获取到相同的ConnectionHolder，截取的代码如下:

if (txObject.isNewConnectionHolder()) {    TransactionSynchronizationManager.bindResource(this.obtainDataSource(), txObject.getConnectionHolder());}

到此，TransactionStatus就创建好了。

5. 获取TransactionInfo

首先看类TransactionAspectSupport中的prepareTransactionInfo。

protected TransactionAspectSupport.TransactionInfo prepareTransactionInfo(@Nullable PlatformTransactionManager tm, @Nullable TransactionAttribute txAttr, String joinpointIdentification, @Nullable TransactionStatus status) {    TransactionAspectSupport.TransactionInfo txInfo = new TransactionAspectSupport.TransactionInfo(tm, txAttr, joinpointIdentification);    if (txAttr != null) {        if (this.logger.isTraceEnabled()) {            this.logger.trace("Getting transaction for [" + txInfo.getJoinpointIdentification() + "]");        }         txInfo.newTransactionStatus(status);    } else if (this.logger.isTraceEnabled()) {        this.logger.trace("Don't need to create transaction for [" + joinpointIdentification + "]: This method isn't transactional.");    }     txInfo.bindToThread();    return txInfo;}

我们细看txInfo.bindToThread();方法。

bindToThread方法在类TransactionAspectSupport.TransactionInfo中，如下代码所示：

private void bindToThread() {    this.oldTransactionInfo = (TransactionAspectSupport.TransactionInfo)TransactionAspectSupport.transactionInfoHolder.get();    TransactionAspectSupport.transactionInfoHolder.set(this);}java.lang.ThreadLocal#get 

java.lang.ThreadLocal类中的get方法如下：

public T get() {    Thread t = Thread.currentThread();    ThreadLocalMap map = getMap(t);    if (map != null) {        ThreadLocalMap.Entry e = map.getEntry(this);        if (e != null) {            @SuppressWarnings("unchecked")            T result = (T)e.value;            return result;        }    }    return setInitialValue();}

bindToThread()的的作用是获取oldTransactionInfo，还有线程有有关。

4. functionTwo方法抛异常后的回滚操作

我们首先看类TransactionAspectSupport中的completeTransactionAfterThrowing方法，如下所示：

protected void completeTransactionAfterThrowing(@Nullable TransactionAspectSupport.TransactionInfo txInfo, Throwable ex) {    if (txInfo != null && txInfo.getTransactionStatus() != null) {        if (this.logger.isTraceEnabled()) {            this.logger.trace("Completing transaction for [" + txInfo.getJoinpointIdentification() + "] after exception: " + ex);        }         if (txInfo.transactionAttribute != null && txInfo.transactionAttribute.rollbackOn(ex)) {            try {                txInfo.getTransactionManager().rollback(txInfo.getTransactionStatus());            } catch (TransactionSystemException var6) {                this.logger.error("Application exception overridden by rollback exception", ex);                var6.initApplicationException(ex);                throw var6;            } catch (Error | RuntimeException var7) {                this.logger.error("Application exception overridden by rollback exception", ex);                throw var7;            }        } else {            try {                txInfo.getTransactionManager().commit(txInfo.getTransactionStatus());            } catch (TransactionSystemException var4) {                this.logger.error("Application exception overridden by commit exception", ex);                var4.initApplicationException(ex);                throw var4;            } catch (Error | RuntimeException var5) {                this.logger.error("Application exception overridden by commit exception", ex);                throw var5;            }        }    }}

txInfo.getTransactionManager().rollback(txInfo.getTransactionStatus());调用transactionManager进行rollback。

接着看AbstractPlatformTransactionManager类中的rollback方法，如下所示：

public final void rollback(TransactionStatus status) throws TransactionException {    if (status.isCompleted()) {        throw new IllegalTransactionStateException("Transaction is already completed - do not call commit or rollback more than once per transaction");    } else {        DefaultTransactionStatus defStatus = (DefaultTransactionStatus)status;        this.processRollback(defStatus, false);    }}

进一步调自身的processRollback，那就继续看类中AbstractPlatformTransactionManager的processRollback方法，如下所示：

private void processRollback(DefaultTransactionStatus status, boolean unexpected) {    try {        boolean unexpectedRollback = unexpected;         try {            this.triggerBeforeCompletion(status);            if (status.hasSavepoint()) {                if (status.isDebug()) {                    this.logger.debug("Rolling back transaction to savepoint");                }                 status.rollbackToHeldSavepoint();            } else if (status.isNewTransaction()) {                if (status.isDebug()) {                    this.logger.debug("Initiating transaction rollback");                }                 this.doRollback(status);            } else {                if (status.hasTransaction()) {                    if (!status.isLocalRollbackOnly() && !this.isGlobalRollbackOnParticipationFailure()) {                        if (status.isDebug()) {this.logger.debug("Participating transaction failed - letting transaction originator decide on rollback");                        }                    } else {                        if (status.isDebug()) {this.logger.debug("Participating transaction failed - marking existing transaction as rollback-only");                        }                         this.doSetRollbackOnly(status);                    }                } else {                    this.logger.debug("Should roll back transaction but cannot - no transaction available");                }                 if (!this.isFailEarlyOnGlobalRollbackOnly()) {                    unexpectedRollback = false;                }            }        } catch (Error | RuntimeException var8) {            this.triggerAfterCompletion(status, 2);            throw var8;        }         this.triggerAfterCompletion(status, 1);        if (unexpectedRollback) {            throw new UnexpectedRollbackException("Transaction rolled back because it has been marked as rollback-only");        }    } finally {        this.cleanupAfterCompletion(status);    } }

this.triggerBeforeCompletion(status) 方法好像释放了连接。

functionTwo不是新事务，所以最后会执行this.doSetRollbackOnly(status)。

进而看类DataSourceTransactionManager中的doSetRollbackOnly方法，如下所示：

protected void doSetRollbackOnly(DefaultTransactionStatus status) {    DataSourceTransactionManager.DataSourceTransactionObject txObject = (DataSourceTransactionManager.DataSourceTransactionObject)status.getTransaction();    if (status.isDebug()) {        this.logger.debug("Setting JDBC transaction [" + txObject.getConnectionHolder().getConnection() + "] rollback-only");    }     txObject.setRollbackOnly();}

接着看方法doSetRollbackOnly中的DataSourceTransactionObject.setRollbackOnly()方法，如下所示：

public void setRollbackOnly() {    this.getConnectionHolder().setRollbackOnly();}

这里，可以看到最终设置的是connectionHolder的rollbackonly属性。

5. functionOne方法尝试提交时的操作

我们首先看TransactionAspectSupport类中的commitTransactionAfterReturning方法，如下所示：

protected void commitTransactionAfterReturning(@Nullable TransactionAspectSupport.TransactionInfo txInfo) {    if (txInfo != null && txInfo.getTransactionStatus() != null) {        if (this.logger.isTraceEnabled()) {            this.logger.trace("Completing transaction for [" + txInfo.getJoinpointIdentification() + "]");        }         txInfo.getTransactionManager().commit(txInfo.getTransactionStatus());    } }

同样的，这里调用transactionManager进行提交。

紧着看AbstractPlatformTransactionManager中的commit方法，如下所示：

public final void commit(TransactionStatus status) throws TransactionException {    if (status.isCompleted()) {        throw new IllegalTransactionStateException("Transaction is already completed - do not call commit or rollback more than once per transaction");    } else {        DefaultTransactionStatus defStatus = (DefaultTransactionStatus)status;        if (defStatus.isLocalRollbackOnly()) {            if (defStatus.isDebug()) {                this.logger.debug("Transactional code has requested rollback");            }             this.processRollback(defStatus, false);        } else if (!this.shouldCommitOnGlobalRollbackOnly() && defStatus.isGlobalRollbackOnly()) {            if (defStatus.isDebug()) {                this.logger.debug("Global transaction is marked as rollback-only but transactional code requested commit");            }             this.processRollback(defStatus, true);        } else {            this.processCommit(defStatus);        }    }}

这个方法判断了一些无法提交的情况，程序这里走第二个分支，部分代码如下:

else if (!this.shouldCommitOnGlobalRollbackOnly() && defStatus.isGlobalRollbackOnly()) {    if (defStatus.isDebug()) {        this.logger.debug("Global transaction is marked as rollback-only but transactional code requested commit");    }     this.processRollback(defStatus, true);}

判断条件为:

1. 全局不是rollbackonly时，也提交(这个可能是一个配置的参数，配合在rollbackonly的时候也提交，也就是出现现在这种情况后，不用回滚，直接提交)

2. 并且全局是rollbackonly

进而看类DefaultTransactionStatus中的isGlobalRollbackOnly方法，如下所示：

public boolean isGlobalRollbackOnly() {    return this.transaction instanceof SmartTransactionObject && ((SmartTransactionObject)this.transaction).isRollbackOnly();}

这里又要满足两个条件：

1. 这里的transaction是DataSourceTransactionObject

DataSourceTransaction继承JdbcTransactionObjectSupport

JdbcTransactionObjectSupport又实现SmartTransactionObject，所以第一个条件满足。

2. DatSourceTransactionObject的RollbackOnly的get和set方法如下：

public void setRollbackOnly() {    this.getConnectionHolder().setRollbackOnly();} public boolean isRollbackOnly() {    return this.getConnectionHolder().isRollbackOnly();}

之前functionTwo方法抛出异常时，就是调用的DataSourceTransactionObject的set方法设置rollbackonly为true，现在再用get方法获取，只要是同一个connectionHolder。

functionOne获取到的rollbackOnly就是true，就会触发回滚，执行this.processRollback(defStatus, true)。

最后再次看类AbstractPlatformTransactionManager中的processRollback方法，如下所示：

private void processRollback(DefaultTransactionStatus status, boolean unexpected) {    try {        boolean unexpectedRollback = unexpected;         try {            this.triggerBeforeCompletion(status);            if (status.hasSavepoint()) {                if (status.isDebug()) {                    this.logger.debug("Rolling back transaction to savepoint");                }                 status.rollbackToHeldSavepoint();            } else if (status.isNewTransaction()) {                if (status.isDebug()) {                    this.logger.debug("Initiating transaction rollback");                }                 this.doRollback(status);            } else {                if (status.hasTransaction()) {                    if (!status.isLocalRollbackOnly() && !this.isGlobalRollbackOnParticipationFailure()) {                        if (status.isDebug()) {this.logger.debug("Participating transaction failed - letting transaction originator decide on rollback");                        }                    } else {                        if (status.isDebug()) {this.logger.debug("Participating transaction failed - marking existing transaction as rollback-only");                        }                         this.doSetRollbackOnly(status);                    }                } else {                    this.logger.debug("Should roll back transaction but cannot - no transaction available");                }                 if (!this.isFailEarlyOnGlobalRollbackOnly()) {                    unexpectedRollback = false;                }            }        } catch (Error | RuntimeException var8) {            this.triggerAfterCompletion(status, 2);            throw var8;        }         this.triggerAfterCompletion(status, 1);        if (unexpectedRollback) {            throw new UnexpectedRollbackException("Transaction rolled back because it has been marked as rollback-only");        }    } finally {        this.cleanupAfterCompletion(status);    }}

到这里unexpectedRollback为true，就抛出了Transaction rolled back because it has been marked as rollback-only这个异常了。

6. 总结

以上就是Transaction silently rolled back because it has been marked as rollback-only错误来分析spring boot的事务机制。

如果有不同意见的，可以在评论区中留言，大家共同进步。

如果你对Knife4j感兴趣，可以参考博文：https://blog.csdn.net/lvoelife/article/details/128114264

来源地址：https://blog.csdn.net/lvoelife/article/details/129165965