spring事物传播属性

PROPAGATION_REQUIRED

Support a current transaction; create a new one if none exists. 

支持一个当前事务;如果不存在，创建一个新的。

This is typically the default setting of a transaction definition, and typically defines a transaction synchronization scope.

默认设置，后面的不懂

PROPAGATION_SUPPORTS

Support a current transaction; execute non-transactionally if none exists. 

支持当前事务；如果不存在当前事务则执行非事务。

 

PROPAGATION_NOT_SUPPORTED

Do not support a current transaction; rather always execute non-transactionally.

不执行当前事务；而是总是执行非事务

PROPAGATION_REQUIRES_NEW

Create a new transaction, suspending the current transaction if one exists. 

创建一个新的事务，如果存在当前事务的话暂停（挂起）当前事务 。

 

PROPAGATION_NESTED

Execute within a nested transaction if a current transaction exists 

如果当前存在事务的话，执行一个嵌套的事务

 

PROPAGATION_NEVER

Do not support a current transaction; throw an exception if a current transaction exists. 

不支持当前事务；如果存在当前事务则抛出一个异常

 

PROPAGATION_MANDATORY

Support a current transaction; throw an exception if no current transaction exists.  

支持当前事务；如果不存在当前事务则抛出一个异常