Spring 事务模板方法设计模式

@Override
protected Object doGetTransaction() {
HibernateTransactionObject txObject = new HibernateTransactionObject();
txObject.setSavepointAllowed(isNestedTransactionAllowed());SessionHolder sessionHolder =
(SessionHolder) TransactionSynchronizationManager.getResource(getSessionFactory());
if (sessionHolder != null) {
if (logger.isDebugEnabled()) {
logger.debug("Found thread-bound Session [" +
SessionFactoryUtils.toString(sessionHolder.getSession()) + "] for Hibernate transaction");
}
txObject.setSessionHolder(sessionHolder);
}
else if (this.hibernateManagedSession) {
try {
Session session = getSessionFactory().getCurrentSession();
if (logger.isDebugEnabled()) {
logger.debug("Found Hibernate-managed Session [" +
SessionFactoryUtils.toString(session) + "] for Spring-managed transaction");
}
txObject.setExistingSession(session);
}
catch (HibernateException ex) {
throw new DataAccessResourceFailureException(
"Could not obtain Hibernate-managed Session for Spring-managed transaction", ex);
}
}if (getDataSource() != null) {
ConnectionHolder conHolder = (ConnectionHolder)
TransactionSynchronizationManager.getResource(getDataSource());
txObject.setConnectionHolder(conHolder);
}return txObject;
}

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

/**
* Create a TransactionStatus for an existing transaction.
*/
private TransactionStatus handleExistingTransaction(
TransactionDefinition definition, Object transaction, boolean debugEnabled)
throws TransactionException {if (definition.getPropagationBehavior() == TransactionDefinition.PROPAGATION_NEVER) {
throw new IllegalTransactionStateException(
"Existing transaction found for transaction marked with propagation 'never'");
}if (definition.getPropagationBehavior() == TransactionDefinition.PROPAGATION_NOT_SUPPORTED) {
if (debugEnabled) {
logger.debug("Suspending current transaction");
}
Object suspendedResources = suspend(transaction);
boolean newSynchronization = (getTransactionSynchronization() == SYNCHRONIZATION_ALWAYS);
return prepareTransactionStatus(
definition, null, false, newSynchronization, debugEnabled, suspendedResources);
}if (definition.getPropagationBehavior() == TransactionDefinition.PROPAGATION_REQUIRES_NEW) {
if (debugEnabled) {
logger.debug("Suspending current transaction, creating new transaction with name [" +
definition.getName() + "]");
}
SuspendedResourcesHolder suspendedResources = suspend(transaction);
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 beginEx) {
resumeAfterBeginException(transaction, suspendedResources, beginEx);
throw beginEx;
}
catch (Error beginErr) {
resumeAfterBeginException(transaction, suspendedResources, beginErr);
throw beginErr;
}
}if (definition.getPropagationBehavior() == TransactionDefinition.PROPAGATION_NESTED) {
if (!isNestedTransactionAllowed()) {
throw new NestedTransactionNotSupportedException(
"Transaction manager does not allow nested transactions by default - " +
"specify 'nestedTransactionAllowed' property with value 'true'");
}
if (debugEnabled) {
logger.debug("Creating nested transaction with name [" + definition.getName() + "]");
}
if (useSavepointForNestedTransaction()) {
// Create savepoint within existing Spring-managed transaction,
// through the SavepointManager API implemented by TransactionStatus.
// Usually uses JDBC 3.0 savepoints. Never activates Spring synchronization.
DefaultTransactionStatus status =
prepareTransactionStatus(definition, transaction, false, false, debugEnabled, null);
status.createAndHoldSavepoint();
return status;
}
else {
// Nested transaction through nested begin and commit/rollback calls.
// Usually only for JTA: Spring synchronization might get activated here
// in case of a pre-existing JTA transaction.
boolean newSynchronization = (getTransactionSynchronization() != SYNCHRONIZATION_NEVER);
DefaultTransactionStatus status = newTransactionStatus(
definition, transaction, true, newSynchronization, debugEnabled, null);
doBegin(transaction, definition);
prepareSynchronization(status, definition);
return status;
}
}// Assumably PROPAGATION_SUPPORTS or PROPAGATION_REQUIRED.
if (debugEnabled) {
logger.debug("Participating in existing transaction");
}
if (isValidateExistingTransaction()) {
if (definition.getIsolationLevel() != TransactionDefinition.ISOLATION_DEFAULT) {
Integer currentIsolationLevel = TransactionSynchronizationManager.getCurrentTransactionIsolationLevel();
if (currentIsolationLevel == null || currentIsolationLevel != definition.getIsolationLevel()) {
Constants isoConstants = DefaultTransactionDefinition.constants;
throw new IllegalTransactionStateException("Participating transaction with definition [" +
definition + "] specifies isolation level which is incompatible with existing transaction: " +
(currentIsolationLevel != null ?
isoConstants.toCode(currentIsolationLevel, DefaultTransactionDefinition.PREFIX_ISOLATION) :
"(unknown)"));
}
}
if (!definition.isReadOnly()) {
if (TransactionSynchronizationManager.isCurrentTransactionReadOnly()) {
throw new IllegalTransactionStateException("Participating transaction with definition [" +
definition + "] is not marked as read-only but existing transaction is");
}
}
}
boolean newSynchronization = (getTransactionSynchronization() != SYNCHRONIZATION_NEVER);
return prepareTransactionStatus(definition, transaction, false, newSynchronization, debugEnabled, null);
}

protected void doBegin(Object transaction, TransactionDefinition definition) {
HibernateTransactionObject txObject = (HibernateTransactionObject) transaction;if (txObject.hasConnectionHolder() && !txObject.getConnectionHolder().isSynchronizedWithTransaction()) {
throw new IllegalTransactionStateException(
"Pre-bound JDBC Connection found! HibernateTransactionManager does not support " +
"running within DataSourceTransactionManager if told to manage the DataSource itself. " +
"It is recommended to use a single HibernateTransactionManager for all transactions " +
"on a single DataSource, no matter whether Hibernate or JDBC access.");
}Session session = null;try {
if (txObject.getSessionHolder() == null || txObject.getSessionHolder().isSynchronizedWithTransaction()) {
Interceptor entityInterceptor = getEntityInterceptor();
Session newSession = (entityInterceptor != null ?
getSessionFactory().openSession(entityInterceptor) : getSessionFactory().openSession());
if (logger.isDebugEnabled()) {
logger.debug("Opened new Session [" + SessionFactoryUtils.toString(newSession) +
"] for Hibernate transaction");
}
txObject.setSession(newSession);
}session = txObject.getSessionHolder().getSession();if (this.prepareConnection && isSameConnectionForEntireSession(session)) {
// We're allowed to change the transaction settings of the JDBC Connection.
if (logger.isDebugEnabled()) {
logger.debug(
"Preparing JDBC Connection of Hibernate Session [" + SessionFactoryUtils.toString(session) + "]");
}
Connection con = session.connection();
Integer previousIsolationLevel = DataSourceUtils.prepareConnectionForTransaction(con, definition);
txObject.setPreviousIsolationLevel(previousIsolationLevel);
}
else {
// Not allowed to change the transaction settings of the JDBC Connection.
if (definition.getIsolationLevel() != TransactionDefinition.ISOLATION_DEFAULT) {
// We should set a specific isolation level but are not allowed to...
throw new InvalidIsolationLevelException(
"HibernateTransactionManager is not allowed to support custom isolation levels: " +
"make sure that its 'prepareConnection' flag is on (the default) and that the " +
"Hibernate connection release mode is set to 'on_close' (SpringTransactionFactory's default). " +
"Make sure that your LocalSessionFactoryBean actually uses SpringTransactionFactory: Your " +
"Hibernate properties should *not* include a 'hibernate.transaction.factory_class' property!");
}
if (logger.isDebugEnabled()) {
logger.debug(
"Not preparing JDBC Connection of Hibernate Session [" + SessionFactoryUtils.toString(session) + "]");
}
}if (definition.isReadOnly() && txObject.isNewSession()) {
// Just set to NEVER in case of a new Session for this transaction.
session.setFlushMode(FlushMode.MANUAL);
}if (!definition.isReadOnly() && !txObject.isNewSession()) {
// We need AUTO or COMMIT for a non-read-only transaction.
FlushMode flushMode = session.getFlushMode();
if (flushMode.lessThan(FlushMode.COMMIT)) {
session.setFlushMode(FlushMode.AUTO);
txObject.getSessionHolder().setPreviousFlushMode(flushMode);
}
}Transaction hibTx;// Register transaction timeout.
int timeout = determineTimeout(definition);
if (timeout != TransactionDefinition.TIMEOUT_DEFAULT) {
// Use Hibernate's own transaction timeout mechanism on Hibernate 3.1+
// Applies to all statements, also to inserts, updates and deletes!
hibTx = session.getTransaction();
hibTx.setTimeout(timeout);
hibTx.begin();
}
else {
// Open a plain Hibernate transaction without specified timeout.
hibTx = session.beginTransaction();
}// Add the Hibernate transaction to the session holder.
txObject.getSessionHolder().setTransaction(hibTx);// Register the Hibernate Session's JDBC Connection for the DataSource, if set.
if (getDataSource() != null) {
Connection con = session.connection();
ConnectionHolder conHolder = new ConnectionHolder(con);
if (timeout != TransactionDefinition.TIMEOUT_DEFAULT) {
conHolder.setTimeoutInSeconds(timeout);
}
if (logger.isDebugEnabled()) {
logger.debug("Exposing Hibernate transaction as JDBC transaction [" + con + "]");
}
TransactionSynchronizationManager.bindResource(getDataSource(), conHolder);
txObject.setConnectionHolder(conHolder);
}// Bind the session holder to the thread.
if (txObject.isNewSessionHolder()) {
TransactionSynchronizationManager.bindResource(getSessionFactory(), txObject.getSessionHolder());
}
txObject.getSessionHolder().setSynchronizedWithTransaction(true);
}catch (Exception ex) {
if (txObject.isNewSession()) {
try {
if (session.getTransaction().isActive()) {
session.getTransaction().rollback();
}
}
catch (Throwable ex2) {
logger.debug("Could not rollback Session after failed transaction begin", ex);
}
finally {
SessionFactoryUtils.closeSession(session);
}
}
throw new CannotCreateTransactionException("Could not open Hibernate Session for transaction", ex);
}
}

@Override
protected void doBegin(Object transaction, TransactionDefinition definition) {
DataSourceTransactionObject txObject = (DataSourceTransactionObject) transaction;
Connection con = null;try {
if (txObject.getConnectionHolder() == null ||
txObject.getConnectionHolder().isSynchronizedWithTransaction()) {
Connection newCon = this.dataSource.getConnection();
if (logger.isDebugEnabled()) {
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);// Switch to manual commit if necessary. This is very expensive in some JDBC drivers,
// so we don't want to do it unnecessarily (for example if we've explicitly
// configured the connection pool to set it already).
if (con.getAutoCommit()) {
txObject.setMustRestoreAutoCommit(true);
if (logger.isDebugEnabled()) {
logger.debug("Switching JDBC Connection [" + con + "] to manual commit");
}
con.setAutoCommit(false);
}
txObject.getConnectionHolder().setTransactionActive(true);int timeout = determineTimeout(definition);
if (timeout != TransactionDefinition.TIMEOUT_DEFAULT) {
txObject.getConnectionHolder().setTimeoutInSeconds(timeout);
}// Bind the session holder to the thread.
if (txObject.isNewConnectionHolder()) {
TransactionSynchronizationManager.bindResource(getDataSource(), txObject.getConnectionHolder());
}
}catch (Exception ex) {
DataSourceUtils.releaseConnection(con, this.dataSource);
throw new CannotCreateTransactionException("Could not open JDBC Connection for transaction", ex);
}
}

/**
* This implementation of commit handles participating in existing
* transactions and programmatic rollback requests.
* Delegates to <code>isRollbackOnly</code>, <code>doCommit</code>
* and <code>rollback</code>.
* @see org.springframework.transaction.TransactionStatus#isRollbackOnly()
* @see #doCommit
* @see #rollback
*/
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");
}DefaultTransactionStatus defStatus = (DefaultTransactionStatus) status;
if (defStatus.isLocalRollbackOnly()) {
if (defStatus.isDebug()) {
logger.debug("Transactional code has requested rollback");
}
processRollback(defStatus);
return;
}
if (!shouldCommitOnGlobalRollbackOnly() && defStatus.isGlobalRollbackOnly()) {
if (defStatus.isDebug()) {
logger.debug("Global transaction is marked as rollback-only but transactional code requested commit");
}
processRollback(defStatus);
// 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");
}
return;
}processCommit(defStatus);
}

/**
* Process an actual commit.
* Rollback-only flags have already been checked and applied.
* @param status object representing the transaction
* @throws TransactionException in case of commit failure
*/
private void processCommit(DefaultTransactionStatus status) throws TransactionException {
try {
boolean beforeCompletionInvoked = false;
try {
prepareForCommit(status);
triggerBeforeCommit(status);
triggerBeforeCompletion(status);
beforeCompletionInvoked = true;
boolean globalRollbackOnly = false;
if (status.isNewTransaction() || isFailEarlyOnGlobalRollbackOnly()) {
globalRollbackOnly = status.isGlobalRollbackOnly();
}
if (status.hasSavepoint()) {
if (status.isDebug()) {
logger.debug("Releasing transaction savepoint");
}
status.releaseHeldSavepoint();
}
else if (status.isNewTransaction()) {
if (status.isDebug()) {
logger.debug("Initiating transaction commit");
}
doCommit(status);
}
// Throw UnexpectedRollbackException if we have a global rollback-only
// marker but still didn't get a corresponding exception from commit.
if (globalRollbackOnly) {
throw new UnexpectedRollbackException(
"Transaction silently rolled back because it has been marked as rollback-only");
}
}
catch (UnexpectedRollbackException ex) {
// can only be caused by doCommit
triggerAfterCompletion(status, TransactionSynchronization.STATUS_ROLLED_BACK);
throw ex;
}
catch (TransactionException ex) {
// can only be caused by doCommit
if (isRollbackOnCommitFailure()) {
doRollbackOnCommitException(status, ex);
}
else {
triggerAfterCompletion(status, TransactionSynchronization.STATUS_UNKNOWN);
}
throw ex;
}
catch (RuntimeException ex) {
if (!beforeCompletionInvoked) {
triggerBeforeCompletion(status);
}
doRollbackOnCommitException(status, ex);
throw ex;
}
catch (Error err) {
if (!beforeCompletionInvoked) {
triggerBeforeCompletion(status);
}
doRollbackOnCommitException(status, err);
throw err;
}// Trigger afterCommit callbacks, with an exception thrown there
// propagated to callers but the transaction still considered as committed.
try {
triggerAfterCommit(status);
}
finally {
triggerAfterCompletion(status, TransactionSynchronization.STATUS_COMMITTED);
}}
finally {
cleanupAfterCompletion(status);
}
}

/**
* 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;
}
}
}
}

/**
* Reset the TransactionInfo ThreadLocal.
* <p>Call this in all cases: exception or normal return!
* @param txInfo information about the current transaction (may be <code>null</code>)
*/
protected void cleanupTransactionInfo(TransactionInfo txInfo) {
if (txInfo != null) {
txInfo.restoreThreadLocalStatus();
}
}