Spring事务杂记

org.springframework.transaction.support.AbstractPlatformTransactionManager#getTransaction

public final TransactionStatus getTransaction(TransactionDefinition definition) throws TransactionException {
       Object transaction = doGetTransaction();

       // Cache debug flag to avoid repeated checks.
       boolean debugEnabled = logger.isDebugEnabled();

       if (definition == null) {
           // Use defaults if no transaction definition given.
           definition = new DefaultTransactionDefinition();
       }

       if (isExistingTransaction(transaction)) {
           // Existing transaction found -> check propagation behavior to find out how to behave.
           return handleExistingTransaction(definition, transaction, debugEnabled);
       }

       // Check definition settings for new transaction.
       if (definition.getTimeout() < TransactionDefinition.TIMEOUT_DEFAULT) {
           throw new InvalidTimeoutException("Invalid transaction timeout", definition.getTimeout());
       }

       // No existing transaction found -> check propagation behavior to find out how to proceed.
       if (definition.getPropagationBehavior() == TransactionDefinition.PROPAGATION_MANDATORY) {
           throw new IllegalTransactionStateException(
                   "No existing transaction found for transaction marked with propagation 'mandatory'");
       }
       else if (definition.getPropagationBehavior() == TransactionDefinition.PROPAGATION_REQUIRED ||
               definition.getPropagationBehavior() == TransactionDefinition.PROPAGATION_REQUIRES_NEW ||
               definition.getPropagationBehavior() == TransactionDefinition.PROPAGATION_NESTED) {
           SuspendedResourcesHolder suspendedResources = suspend(null);
           if (debugEnabled) {
               logger.debug("Creating new transaction with name [" + definition.getName() + "]: " + definition);
           }
           try {
               boolean newSynchronization = (getTransactionSynchronization() != SYNCHRONIZATION_NEVER);
               DefaultTransactionStatus status = newTransactionStatus(
                       definition, transaction, true, newSynchronization, debugEnabled, suspendedResources);
               doBegin(transaction, definition);
               prepareSynchronization(status, definition);
               return status;
           }
           catch (RuntimeException ex) {
               resume(null, suspendedResources);
               throw ex;
           }
           catch (Error err) {
               resume(null, suspendedResources);
               throw err;
           }
       }
       else {
           // Create "empty" transaction: no actual transaction, but potentially synchronization.
           if (definition.getIsolationLevel() != TransactionDefinition.ISOLATION_DEFAULT && logger.isWarnEnabled()) {
               logger.warn("Custom isolation level specified but no actual transaction initiated; " +
                       "isolation level will effectively be ignored: " + definition);
           }
           boolean newSynchronization = (getTransactionSynchronization() == SYNCHRONIZATION_ALWAYS);
           return prepareTransactionStatus(definition, null, true, newSynchronization, debugEnabled, null);
       }
   }

属性处理

    protected TransactionInfo prepareTransactionInfo(PlatformTransactionManager tm,
            TransactionAttribute txAttr, String joinpointIdentification, TransactionStatus status) {

        TransactionInfo txInfo = new TransactionInfo(tm, txAttr, joinpointIdentification);
        if (txAttr != null) {
            // We need a transaction for this method...
            if (logger.isTraceEnabled()) {
                logger.trace("Getting transaction for [" + txInfo.getJoinpointIdentification() + "]");
            }
            // The transaction manager will flag an error if an incompatible tx already exists.
            txInfo.newTransactionStatus(status);
        }
        else {
            // The TransactionInfo.hasTransaction() method will return false. We created it only
            // to preserve the integrity of the ThreadLocal stack maintained in this class.
            if (logger.isTraceEnabled())
                logger.trace("Don't need to create transaction for [" + joinpointIdentification +
                        "]: This method isn't transactional.");
        }

        // We always bind the TransactionInfo to the thread, even if we didn't create
        // a new transaction here. This guarantees that the TransactionInfo stack
        // will be managed correctly even if no transaction was created by this aspect.
        txInfo.bindToThread();
        return txInfo;
    }

image.png image.png

protected final class TransactionInfo {

        private final PlatformTransactionManager transactionManager;

        private final TransactionAttribute transactionAttribute;

        private final String joinpointIdentification;

        private TransactionStatus transactionStatus;

        private TransactionInfo oldTransactionInfo;
        
}

org.springframework.transaction.interceptor.TransactionAspectSupport#invokeWithinTransaction

protected Object invokeWithinTransaction(Method method, Class<?> targetClass, final InvocationCallback invocation)
            throws Throwable {

        // If the transaction attribute is null, the method is non-transactional.
        final TransactionAttribute txAttr = getTransactionAttributeSource().getTransactionAttribute(method, targetClass);
        final PlatformTransactionManager tm = determineTransactionManager(txAttr);
        final String joinpointIdentification = methodIdentification(method, targetClass, txAttr);

        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;
        }

        else {
            final ThrowableHolder throwableHolder = new ThrowableHolder();

            // It's a CallbackPreferringPlatformTransactionManager: pass a TransactionCallback in.
            try {
                Object result = ((CallbackPreferringPlatformTransactionManager) tm).execute(txAttr,
                        new TransactionCallback<Object>() {
                            @Override
                            public Object doInTransaction(TransactionStatus status) {
                                TransactionInfo txInfo = prepareTransactionInfo(tm, txAttr, joinpointIdentification, status);
                                try {
                                    return invocation.proceedWithInvocation();
                                }
                                catch (Throwable ex) {
                                    if (txAttr.rollbackOn(ex)) {
                                        // A RuntimeException: will lead to a rollback.
                                        if (ex instanceof RuntimeException) {
                                            throw (RuntimeException) ex;
                                        }
                                        else {
                                            throw new ThrowableHolderException(ex);
                                        }
                                    }
                                    else {
                                        // A normal return value: will lead to a commit.
                                        throwableHolder.throwable = ex;
                                        return null;
                                    }
                                }
                                finally {
                                    cleanupTransactionInfo(txInfo);
                                }
                            }
                        });

                // Check result state: It might indicate a Throwable to rethrow.
                if (throwableHolder.throwable != null) {
                    throw throwableHolder.throwable;
                }
                return result;
            }
            catch (ThrowableHolderException ex) {
                throw ex.getCause();
            }
            catch (TransactionSystemException ex2) {
                if (throwableHolder.throwable != null) {
                    logger.error("Application exception overridden by commit exception", throwableHolder.throwable);
                    ex2.initApplicationException(throwableHolder.throwable);
                }
                throw ex2;
            }
            catch (Throwable ex2) {
                if (throwableHolder.throwable != null) {
                    logger.error("Application exception overridden by commit exception", throwableHolder.throwable);
                }
                throw ex2;
            }
        }
    }

    @Override
    public Object invoke(final MethodInvocation invocation) throws Throwable {
        // Work out the target class: may be {@code null}.
        // The TransactionAttributeSource should be passed the target class
        // as well as the method, which may be from an interface.
        Class<?> targetClass = (invocation.getThis() != null ? AopUtils.getTargetClass(invocation.getThis()) : null);

        // Adapt to TransactionAspectSupport's invokeWithinTransaction...
        return invokeWithinTransaction(invocation.getMethod(), targetClass, new InvocationCallback() {
            @Override
            public Object proceedWithInvocation() throws Throwable {
                return invocation.proceed();
            }
        });
    }

这是切面AOP的包
org.springframework.aop.framework.ReflectiveMethodInvocation#proceed

@Override
    public Object proceed() throws Throwable {
        //  We start with an index of -1 and increment early.
        if (this.currentInterceptorIndex == this.interceptorsAndDynamicMethodMatchers.size() - 1) {
            return invokeJoinpoint();
        }

        Object interceptorOrInterceptionAdvice =
                this.interceptorsAndDynamicMethodMatchers.get(++this.currentInterceptorIndex);
        if (interceptorOrInterceptionAdvice instanceof InterceptorAndDynamicMethodMatcher) {
            // Evaluate dynamic method matcher here: static part will already have
            // been evaluated and found to match.
            InterceptorAndDynamicMethodMatcher dm =
                    (InterceptorAndDynamicMethodMatcher) interceptorOrInterceptionAdvice;
            if (dm.methodMatcher.matches(this.method, this.targetClass, this.arguments)) {
                return dm.interceptor.invoke(this);
            }
            else {
                // Dynamic matching failed.
                // Skip this interceptor and invoke the next in the chain.
                return proceed();
            }
        }
        else {
            // It's an interceptor, so we just invoke it: The pointcut will have
            // been evaluated statically before this object was constructed.
            return ((MethodInterceptor) interceptorOrInterceptionAdvice).invoke(this);
        }
    }

上面的反射包会走到下面的类，

    /**
     * Implementation of AOP Alliance MethodInvocation used by this AOP proxy.
     */
    private static class CglibMethodInvocation extends ReflectiveMethodInvocation {

        private final MethodProxy methodProxy;

        private final boolean publicMethod;

        public CglibMethodInvocation(Object proxy, Object target, Method method, Object[] arguments,
                Class<?> targetClass, List<Object> interceptorsAndDynamicMethodMatchers, MethodProxy methodProxy) {

            super(proxy, target, method, arguments, targetClass, interceptorsAndDynamicMethodMatchers);
            this.methodProxy = methodProxy;
            this.publicMethod = Modifier.isPublic(method.getModifiers());
        }

        /**
         * Gives a marginal performance improvement versus using reflection to
         * invoke the target when invoking public methods.
         */
        @Override
        protected Object invokeJoinpoint() throws Throwable {
            if (this.publicMethod) {
                return this.methodProxy.invoke(this.target, this.arguments);
            }
            else {
                return super.invokeJoinpoint();
            }
        }
    }

反射invoke后会走到真正的方法
org.springframework.cglib.proxy.MethodProxy#invoke

    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        MethodInvocation invocation;
        Object oldProxy = null;
        boolean setProxyContext = false;

        TargetSource targetSource = this.advised.targetSource;
        Class<?> targetClass = null;
        Object target = null;

        try {
            if (!this.equalsDefined && AopUtils.isEqualsMethod(method)) {
                // The target does not implement the equals(Object) method itself.
                return equals(args[0]);
            }
            else if (!this.hashCodeDefined && AopUtils.isHashCodeMethod(method)) {
                // The target does not implement the hashCode() method itself.
                return hashCode();
            }
            else if (method.getDeclaringClass() == DecoratingProxy.class) {
                // There is only getDecoratedClass() declared -> dispatch to proxy config.
                return AopProxyUtils.ultimateTargetClass(this.advised);
            }
            else if (!this.advised.opaque && method.getDeclaringClass().isInterface() &&
                    method.getDeclaringClass().isAssignableFrom(Advised.class)) {
                // Service invocations on ProxyConfig with the proxy config...
                return AopUtils.invokeJoinpointUsingReflection(this.advised, method, args);
            }

            Object retVal;

            if (this.advised.exposeProxy) {
                // Make invocation available if necessary.
                oldProxy = AopContext.setCurrentProxy(proxy);
                setProxyContext = true;
            }

            // May be null. Get as late as possible to minimize the time we "own" the target,
            // in case it comes from a pool.
            target = targetSource.getTarget();
            if (target != null) {
                targetClass = target.getClass();
            }

            // Get the interception chain for this method.
            List<Object> chain = this.advised.getInterceptorsAndDynamicInterceptionAdvice(method, targetClass);

            // Check whether we have any advice. If we don't, we can fallback on direct
            // reflective invocation of the target, and avoid creating a MethodInvocation.
            if (chain.isEmpty()) {
                // We can skip creating a MethodInvocation: just invoke the target directly
                // Note that the final invoker must be an InvokerInterceptor so we know it does
                // nothing but a reflective operation on the target, and no hot swapping or fancy proxying.
                Object[] argsToUse = AopProxyUtils.adaptArgumentsIfNecessary(method, args);
                retVal = AopUtils.invokeJoinpointUsingReflection(target, method, argsToUse);
            }
            else {
                // We need to create a method invocation...
                invocation = new ReflectiveMethodInvocation(proxy, target, method, args, targetClass, chain);
                // Proceed to the joinpoint through the interceptor chain.
                retVal = invocation.proceed();
            }

            // Massage return value if necessary.
            Class<?> returnType = method.getReturnType();
            if (retVal != null && retVal == target &&
                    returnType != Object.class && returnType.isInstance(proxy) &&
                    !RawTargetAccess.class.isAssignableFrom(method.getDeclaringClass())) {
                // Special case: it returned "this" and the return type of the method
                // is type-compatible. Note that we can't help if the target sets
                // a reference to itself in another returned object.
                retVal = proxy;
            }
            else if (retVal == null && returnType != Void.TYPE && returnType.isPrimitive()) {
                throw new AopInvocationException(
                        "Null return value from advice does not match primitive return type for: " + method);
            }
            return retVal;
        }
        finally {
            if (target != null && !targetSource.isStatic()) {
                // Must have come from TargetSource.
                targetSource.releaseTarget(target);
            }
            if (setProxyContext) {
                // Restore old proxy.
                AopContext.setCurrentProxy(oldProxy);
            }
        }
    }

org.springframework.aop.framework.JdkDynamicAopProxy#invoke

public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        MethodInvocation invocation;
        Object oldProxy = null;
        boolean setProxyContext = false;

        TargetSource targetSource = this.advised.targetSource;
        Class<?> targetClass = null;
        Object target = null;

        try {
            if (!this.equalsDefined && AopUtils.isEqualsMethod(method)) {
                // The target does not implement the equals(Object) method itself.
                return equals(args[0]);
            }
            else if (!this.hashCodeDefined && AopUtils.isHashCodeMethod(method)) {
                // The target does not implement the hashCode() method itself.
                return hashCode();
            }
            else if (method.getDeclaringClass() == DecoratingProxy.class) {
                // There is only getDecoratedClass() declared -> dispatch to proxy config.
                return AopProxyUtils.ultimateTargetClass(this.advised);
            }
            else if (!this.advised.opaque && method.getDeclaringClass().isInterface() &&
                    method.getDeclaringClass().isAssignableFrom(Advised.class)) {
                // Service invocations on ProxyConfig with the proxy config...
                return AopUtils.invokeJoinpointUsingReflection(this.advised, method, args);
            }

            Object retVal;

            if (this.advised.exposeProxy) {
                // Make invocation available if necessary.
                oldProxy = AopContext.setCurrentProxy(proxy);
                setProxyContext = true;
            }

            // May be null. Get as late as possible to minimize the time we "own" the target,
            // in case it comes from a pool.
            target = targetSource.getTarget();
            if (target != null) {
                targetClass = target.getClass();
            }

            // Get the interception chain for this method.
            List<Object> chain = this.advised.getInterceptorsAndDynamicInterceptionAdvice(method, targetClass);

            // Check whether we have any advice. If we don't, we can fallback on direct
            // reflective invocation of the target, and avoid creating a MethodInvocation.
            if (chain.isEmpty()) {
                // We can skip creating a MethodInvocation: just invoke the target directly
                // Note that the final invoker must be an InvokerInterceptor so we know it does
                // nothing but a reflective operation on the target, and no hot swapping or fancy proxying.
                Object[] argsToUse = AopProxyUtils.adaptArgumentsIfNecessary(method, args);
                retVal = AopUtils.invokeJoinpointUsingReflection(target, method, argsToUse);
            }
            else {
                // We need to create a method invocation...
                invocation = new ReflectiveMethodInvocation(proxy, target, method, args, targetClass, chain);
                // Proceed to the joinpoint through the interceptor chain.
                retVal = invocation.proceed();
            }

            // Massage return value if necessary.
            Class<?> returnType = method.getReturnType();
            if (retVal != null && retVal == target &&
                    returnType != Object.class && returnType.isInstance(proxy) &&
                    !RawTargetAccess.class.isAssignableFrom(method.getDeclaringClass())) {
                // Special case: it returned "this" and the return type of the method
                // is type-compatible. Note that we can't help if the target sets
                // a reference to itself in another returned object.
                retVal = proxy;
            }
            else if (retVal == null && returnType != Void.TYPE && returnType.isPrimitive()) {
                throw new AopInvocationException(
                        "Null return value from advice does not match primitive return type for: " + method);
            }
            return retVal;
        }
        finally {
            if (target != null && !targetSource.isStatic()) {
                // Must have come from TargetSource.
                targetSource.releaseTarget(target);
            }
            if (setProxyContext) {
                // Restore old proxy.
                AopContext.setCurrentProxy(oldProxy);
            }
        }
    }

获取目标类
TargetSource targetSource = this.advised.targetSource;

image.png

List<Object> chain = this.advised.getInterceptorsAndDynamicInterceptionAdvice(method, targetClass);
通过链，创建invocation
执行方法
retVal = invocation.proceed();

会走到
org.springframework.transaction.interceptor.TransactionInterceptor#invoke

    public Object invoke(final MethodInvocation invocation) throws Throwable {
        // Work out the target class: may be {@code null}.
        // The TransactionAttributeSource should be passed the target class
        // as well as the method, which may be from an interface.
        Class<?> targetClass = (invocation.getThis() != null ? AopUtils.getTargetClass(invocation.getThis()) : null);

        // Adapt to TransactionAspectSupport's invokeWithinTransaction...
        return invokeWithinTransaction(invocation.getMethod(), targetClass, new InvocationCallback() {
            @Override
            public Object proceedWithInvocation() throws Throwable {
                return invocation.proceed();
            }
        });
    }

很明显，有进行事务处理的逻辑

TransactionInfo txInfo = createTransactionIfNecessary(tm, txAttr, joinpointIdentification);

image.png

调用路线：
org.springframework.aop.framework.CglibAopProxy.DynamicAdvisedInterceptor#intercept
org.springframework.aop.framework.CglibAopProxy.CglibMethodInvocation
org.springframework.aop.framework.CglibAopProxy#processReturnType

org.springframework.aop.framework.JdkDynamicAopProxy#invoke

chain

org.springframework.aop.framework.ReflectiveMethodInvocation#proceed
org.springframework.transaction.interceptor.TransactionInterceptor#invoke
org.springframework.transaction.interceptor.TransactionAspectSupport#invokeWithinTransaction

• org.springframework.transaction.interceptor.TransactionAspectSupport#createTransactionIfNecessary
• org.springframework.transaction.support.AbstractPlatformTransactionManager#getTransaction
• org.springframework.transaction.support.AbstractPlatformTransactionManager#handleExistingTransaction
• org.springframework.transaction.interceptor.TransactionAspectSupport#prepareTransactionInfo
  回调
  org.springframework.aop.framework.ReflectiveMethodInvocation#proceed

org.springframework.aop.framework.ReflectiveMethodInvocation#invokeJoinpoint
org.springframework.aop.support.AopUtils#invokeJoinpointUsingReflection
java.lang.reflect.Method#invoke
com.gongdao.middleware.api.impl.LocalServiceImpl#newTransitionMethod
org.springframework.transaction.interceptor.TransactionAspectSupport#cleanupTransactionInfo
org.springframework.transaction.interceptor.TransactionAspectSupport#cleanupTransactionInfo
org.springframework.transaction.interceptor.TransactionAspectSupport.TransactionInfo#restoreThreadLocalStatus
org.springframework.transaction.interceptor.TransactionAspectSupport#commitTransactionAfterReturning
org.springframework.transaction.support.AbstractPlatformTransactionManager#commit
org.springframework.transaction.support.AbstractPlatformTransactionManager#processCommit
com.gongdao.middleware.db.GongDaoDataSourceTransactionManager#doCommit
org.springframework.transaction.support.AbstractPlatformTransactionManager#triggerAfterCommit
org.springframework.transaction.support.AbstractPlatformTransactionManager#triggerAfterCompletion
......
org.springframework.transaction.support.AbstractPlatformTransactionManager#cleanupAfterCompletion
com.gongdao.middleware.db.GongDaoDataSourceTransactionManager#doCleanupAfterCompletion

image.png