feat:事物源码done

Author: wxasacoder

spring-jdbc/src/main/java/org/springframework/jdbc/datasource/DataSourceTransactionManager.java

@@ -359,7 +359,7 @@ protected void doSetRollbackOnly(DefaultTransactionStatus status) {
 			logger.debug("Setting JDBC transaction [" + txObject.getConnectionHolder().getConnection() +
 					"] rollback-only");
 		}
-		txObject.setRollbackOnly();
+		txObject.setRollbackOnly(); // 将trxInfo中的status中的tansacation中的connectionholder中的rollback only设为true
 	}
 
 	@Override

spring-test/src/main/java/org/springframework/wx/tx/StudentService.java

@@ -28,16 +28,15 @@ public void insertStudentBatch(){
 
 //		new Thread(()->{
 //			System.out.println(Thread.currentThread().getName());
-//			try {
+		try {
 			studentService.insertStudentOne();
-//			} catch (Exception e){
-//
-//			}
+		} catch (Exception e){
+		}
 //		},"i am a new thread ").run();
 //		studentService.insertStudentTWO();
 	}
 
-	@Transactional(rollbackFor = Exception.class,propagation = Propagation.REQUIRED )
+	@Transactional(rollbackFor = Exception.class,propagation = Propagation.REQUIRED)
 	public void insertStudentOne(){
 		System.err.println("-----------------------------------" + Thread.currentThread().getName());
 		String sql = "INSERT INTO student(name,age,gender) values ('1同学',112,1)";

spring-tx/src/main/java/org/springframework/transaction/interceptor/TransactionAspectSupport.java

@@ -637,7 +637,7 @@ protected TransactionInfo prepareTransactionInfo(@Nullable PlatformTransactionMa
 		// 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();
+		txInfo.bindToThread(); // 将当前的manager绑定到当前的线程中，但是老的manager页放入新的manager的older变量中
 		return txInfo;
 	}
 

spring-tx/src/main/java/org/springframework/transaction/support/AbstractPlatformTransactionManager.java

@@ -699,15 +699,16 @@ public final void commit(TransactionStatus status) throws TransactionException {
 			processRollback(defStatus, false);
 			return;
 		}
-
+		// 后者此处回去检测 txInfo中的status中的connectionHolder中的connection中的rollBackOnly标志
+		// 如果为true则直接回滚
 		if (!shouldCommitOnGlobalRollbackOnly() && defStatus.isGlobalRollbackOnly()) {
 			if (defStatus.isDebug()) {
 				logger.debug("Global transaction is marked as rollback-only but transactional code requested commit");
 			}
 			processRollback(defStatus, true);
 			return;
 		}
-
+		// 直接提交
 		processCommit(defStatus);
 	}
 
@@ -727,21 +728,21 @@ private void processCommit(DefaultTransactionStatus status) throws TransactionEx
 				triggerBeforeCommit(status);
 				triggerBeforeCompletion(status);
 				beforeCompletionInvoked = true;
-
+				// 是否有回滚点，有回滚点其实意味着是子事物则需要延迟提交待到父亲事物一起提交
 				if (status.hasSavepoint()) {
 					if (status.isDebug()) {
 						logger.debug("Releasing transaction savepoint");
 					}
 					unexpectedRollback = status.isGlobalRollbackOnly();
 					status.releaseHeldSavepoint();
 				}
-				else if (status.isNewTransaction()) {
+				else if (status.isNewTransaction()) { // 如果是第一个connection则直接提交，第一个connection意味着是事物方法调用的根
 					if (status.isDebug()) {
 						logger.debug("Initiating transaction commit");
 					}
 					unexpectedRollback = status.isGlobalRollbackOnly();
 					doCommit(status);
-				}
+				} // 对于使用的一个事物会到，此处，也就是说ab都是require，a调用b，b在提交的时候会走到这里
 				else if (isFailEarlyOnGlobalRollbackOnly()) {
 					unexpectedRollback = status.isGlobalRollbackOnly();
 				}
@@ -754,7 +755,7 @@ else if (isFailEarlyOnGlobalRollbackOnly()) {
 				}
 			}
 			catch (UnexpectedRollbackException ex) {
-				// can only be caused by doCommit
+				// can only be caused by doCommit //// 执行向TrxManger中注册同步器（afterRollback的逻辑）
 				triggerAfterCompletion(status, TransactionSynchronization.STATUS_ROLLED_BACK);
 				throw ex;
 			}
@@ -763,7 +764,7 @@ else if (isFailEarlyOnGlobalRollbackOnly()) {
 				if (isRollbackOnCommitFailure()) {
 					doRollbackOnCommitException(status, ex);
 				}
-				else {
+				else { // 执行向TrxManger中注册同步器，该同步器可以实现afterCommit和AfterRollback的执行逻辑
 					triggerAfterCompletion(status, TransactionSynchronization.STATUS_UNKNOWN);
 				}
 				throw ex;