- 处理提交流程图
- 传播机制图
- AbstractPlatformTransactionManager的processCommit处理提交
-
- AbstractTransactionStatus的releaseHeldSavepoint释放保存点
-
- JdbcTransactionObjectSupport的releaseSavepoint释放保存点
- DataSourceTransactionManager的doCommit提交
处理提交流程图
传播机制图
AbstractPlatformTransactionManager的processCommit处理提交
其实这个跟处理回滚很像，先处理保存点，然后处理新事务，如果不是新事务不会真正提交，要等外层是新事务的才提交，最后根据条件执行数据清除,线程的私有资源解绑，重置连接自动提交，隔离级别，是否只读，释放连接，恢复挂起事务等。
private void processCommit(DefaultTransactionStatus status) throws TransactionException {
try {
boolean beforeCompletionInvoked = false;
try {
boolean unexpectedRollback = false;
prepareForCommit(status);
triggerBeforeCommit(status);//提交前回调
triggerBeforeCompletion(status);//提交完成前回调
beforeCompletionInvoked = true;
if (status.hasSavepoint()) {
//有保存点
if (status.isDebug()) {
logger.debug("Releasing transaction savepoint");
}
unexpectedRollback = status.isGlobalRollbackOnly();//是否有全局回滚标记
status.releaseHeldSavepoint();
}
else if (status.isNewTransaction()) {
//当前状态是新事务
if (status.isDebug()) {
logger.debug("Initiating transaction commit");
}
unexpectedRollback = status.isGlobalRollbackOnly();
doCommit(status);//真正的提交
}
else if (isFailEarlyOnGlobalRollbackOnly()) {
unexpectedRollback = status.isGlobalRollbackOnly();
}
// Throw UnexpectedRollbackException if we have a global rollback-only
// marker but still didn't get a corresponding exception from commit.
if (unexpectedRollback) {
//有全局回滚标记就报异常
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 | Error ex) {
if (!beforeCompletionInvoked) {
triggerBeforeCompletion(status);
}
doRollbackOnCommitException(status, ex);
throw ex;
}
// Trigger afterCommit callbacks, with an exception thrown there
// propagated to callers but the transaction still considered as committed.
try {
triggerAfterCommit(status);//提交后回调
}
finally {
//提交后清除线程私同步状态
triggerAfterCompletion(status, TransactionSynchronization.STATUS_COMMITTED);
}
}
finally {
//根据条件，完成后数据清除,和线程的私有资源解绑，重置连接自动提交，隔离级别，是否只读，释放连接，恢复挂起事务等
cleanupAfterCompletion(status);
}
}
AbstractTransactionStatus的releaseHeldSavepoint释放保存点
如果没有异常回滚的话，要释放保存点。
public void releaseHeldSavepoint() throws TransactionException {
Object savepoint = getSavepoint();
if (savepoint == null) {
throw new TransactionUsageException(
"Cannot release savepoint - no savepoint associated with current transaction");
}
getSavepointManager().releaseSavepoint(savepoint);
setSavepoint(null);
}
JdbcTransactionObjectSupport的releaseSavepoint释放保存点
其实就是JDBC连接释放保存点。
@Override
public void releaseSavepoint(Object savepoint) throws TransactionException {
ConnectionHolder conHolder = getConnectionHolderForSavepoint();
try {
conHolder.getConnection().releaseSavepoint((Savepoint) savepoint);
}
catch (Throwable ex) {
logger.debug("Could not explicitly release JDBC savepoint", ex);
}
}
DataSourceTransactionManager的doCommit提交
获取JDBC的连接提交。
@Override
protected void doCommit(DefaultTransactionStatus status) {
DataSourceTransactionObject txObject = (DataSourceTransactionObject) status.getTransaction();
Connection con = txObject.getConnectionHolder().getConnection();
if (status.isDebug()) {
logger.debug("Committing JDBC transaction on Connection [" + con + "]");
}
try {
con.commit();//JDBC连接提交
}
catch (SQLException ex) {
throw new TransactionSystemException("Could not commit JDBC transaction", ex);
}
}
大致的几个逻辑都讲完了，但是细节没讲，下次讲讲一些细节，现在对这个流程有大概了解就行。比如一些线程私有变量的作用，还有一些传播机制提交和回滚上的一些区别，顺便总结下。
好了，今天就到这里了，希望对学习理解有帮助，大神看见勿喷，仅为自己的学习理解，能力有限，请多包涵。