PROPAGATION_REQUIRES_NEW事务管理中的变量

PROPAGATION_REQUIRES_NEW传播方式对于第二个事务，会产生一个全新的Connection来处理.两个连接的操作类似于:

 Connection con1 = ds.getConnection();
 con1.setAutoCommit(false );
 con1.executeUpdate(sql1);
 con1.executeUpdate(sql2);
 ...
 Connection con2 = ds.getConnection();
 con2.setAutoCommit(false );
 con2.executeUpdate(sql1);
 con2.exeucteUpdate(sql2);
 ...
 con2.commit();
 con2.setAutoCommit(true );
 con2.close();

 con1.executeUpdate(sqln);
 ...
 con1.commit();
 con1.setAutoCommit(false );
 con1.close();<pre></pre>

Spring事务管理中事务涉及的变量主要有:

变量在两事务(第一个事务为PROPAGATION_REQUIRED,第二个事务为PROPAGATION_REQUIRES_NEW)创建、执行、完成过程中的变化如下:

 

第一个事务
	TransStatus1			Transaction1			ConnectionHolder1
	Transaction	Transaction1		ConnectionHolder	ConnectionHolder1		SynchronizedWithTransaction	TRUE
	newTransaction	TRUE				Connection	con1
	newSynchronization	TRUE		resource
	suspendedResources	null		key	dataSource		Synchronizations
	savepoint	null		value	ConnectionHolder1		ArrayList1	empty
第二个事务:doGetTransaction
	Transaction2
	ConnectionHolder	ConnectionHolder1
doSuspendTransaction
	Transaction2			SuspendedResourcesHolder1
	ConnectionHolder	null		suspendedSynchronizations	ArrayList1
			suspendedResources	ConnectionHolder1
	resource
	null			Synchronizations
				null
doBegin
	TransStatus2			Transaction2			ConnectionHolder2
	Transaction	Transaction2		ConnectionHolder	ConnectionHolder2		SynchronizedWithTransaction	TRUE
	newTransaction	TRUE				Connection	con2
	newSynchronization	TRUE		resource
	suspendedResources	SuspendedResourcesHolder1		key	dataSource		Synchronizations
			value	ConnectionHolder2		ArrayList2	empty
	savepoine	null
triggerBeforeCommit	triggerBeforeCompletion	doCommit:con2.commit	triggerAfterCompletion
doCleanupAfterCompletion
con2恢复autoCommit与isolationLevel		resource			Synchronizations
关闭连接		null			null
resume
已经恢复到第一个事务doBegin刚完成状态		resource			Synchronizations
	key	dataSource		ArrayList1	empty
	value	ConnectionHolder1

源码:

 public   void  addEmployee(Employee employee)  throws  SQLException {
   transactionTemplate.execute(new  TransactionCallback() {
     public  Object doInTransaction(TransactionStatus ts) {
       try  {
         jdbcTemplate.update("INSERT INTO Employee (username,age) VALUES(?, ?)" ,
           new  Object[]{ "lizi" , new  Integer( 22 )});
         departmentDao.addDepartment();
         jdbcTemplate.update("INSERT INTO Employee (username,age) VALUES(?, ?)" ,
           new  Object[]{ "lijun" , new  Integer( 55 )});
         System.out.println("更新成功" );

       } catch  (Exception ex) {
         ex.printStackTrace();
         System.out.println("更新失败" );
         ts.setRollbackOnly();
       }
       //ts.setRollbackOnly();
       return   null ;
     }
   });
 }

 //DepartmentDao.java
 public   void  setTransactionTemplate(
     TransactionTemplate deptTransactionTemplate) {
   this .transactionTemplate = deptTransactionTemplate;
   deptTransactionTemplate.setPropagationBehavior(TransactionDefinition.PROPAGATION_REQUIRES_NEW);

   DataSourceTransactionManager manager = (DataSourceTransactionManager)deptTransactionTemplate.getTransactionManager();
   DataSource ds = manager.getDataSource();

   jdbcTemplate = new  JdbcTemplate(ds);
 }

 public   void  addDepartment() {
   transactionTemplate.execute(new  TransactionCallback() {

     public  Object doInTransaction(TransactionStatus status) {
       try  {
         jdbcTemplate.update("insert into department (dept,deptName) values('IT','IT department')" );
       } catch  (Exception ex) {
         ex.printStackTrace();
         status.setRollbackOnly();
       }
       return   null ;
     }

   });
 }