spring事物传播机制与隔离级别

/** 
* @date 2006-11-24 
* @note 转载自http://www.javaeye.com/topic/35907?page=1
*/ 
********TransactionDefinition 接口定义*******************
/** 
      * Support a current transaction, create a new one if none exists. 
      * Analogous to EJB transaction attribute of the same name. 
      * 
This is typically the default setting of a transaction definition. 
      */ 
     int PROPAGATION_REQUIRED = 0; 
  
     /** 
      * Support a current transaction, execute non-transactionally if none exists. 
      * Analogous to EJB transaction attribute of the same name. 
      * 

Note: For transaction managers with transaction synchronization, 
      * PROPAGATION_SUPPORTS is slightly different from no transaction at all, 
      * as it defines a transaction scopp that synchronization will apply for. 
      * As a consequence, the same resources (JDBC Connection, Hibernate Session, etc) 
      * will be shared for the entire specified scope. Note that this depends on 
      * the actual synchronization configuration of the transaction manager. 
      * @see org.springframework.transaction.support.AbstractPlatformTransactionManager#setTransactionSynchronization 
      */ 
     int PROPAGATION_SUPPORTS = 1; 
  
     /** 
      * Support a current transaction, throw an exception if none exists. 
      * Analogous to EJB transaction attribute of the same name. 
      */ 
     int PROPAGATION_MANDATORY = 2; 
  
     /** 
      * Create a new transaction, suspend the current transaction if one exists. 
      * Analogous to EJB transaction attribute of the same name. 
      * 

Note: Actual transaction suspension will not work on out-of-the-box 
      * on all transaction managers. This in particular applies to JtaTransactionManager, 
      * which requires the javax.transaction.TransactionManager to be 
      * made available it to it (which is server-specific in standard J2EE). 
      * @see org.springframework.transaction.jta.JtaTransactionManager#setTransactionManager 
      */ 
     int PROPAGATION_REQUIRES_NEW = 3; 
  
     /** 
      * Execute non-transactionally, suspend the current transaction if one exists. 
      * Analogous to EJB transaction attribute of the same name. 
      * 

Note: Actual transaction suspension will not work on out-of-the-box 
      * on all transaction managers. This in particular applies to JtaTransactionManager, 
      * which requires the javax.transaction.TransactionManager to be 
      * made available it to it (which is server-specific in standard J2EE). 
      * @see org.springframework.transaction.jta.JtaTransactionManager#setTransactionManager 
      */ 
     int PROPAGATION_NOT_SUPPORTED = 4; 
  
     /** 
      * Execute non-transactionally, throw an exception if a transaction exists. 
      * Analogous to EJB transaction attribute of the same name. 
      */ 
     int PROPAGATION_NEVER = 5; 
  
     /** 
      * Execute within a nested transaction if a current transaction exists, 
      * behave like PROPAGATION_REQUIRED else. There is no analogous feature in EJB. 
      * 

Note: Actual creation of a nested transaction will only work on specific 
      * transaction managers. Out of the box, this only applies to the JDBC 
      * DataSourceTransactionManager when working on a JDBC 3.0 driver. 
      * Some JTA providers might support nested transactions as well. 
      * @see org.springframework.jdbc.datasource.DataSourceTransactionManager 
      */ 
     int PROPAGATION_NESTED = 6; 

*************************************************************************
在这篇文章里，他用两个嵌套的例子辅助分析，我这里直接引用了。
********************sample***********************
ServiceA { 
       
     /** 
      * 事务属性配置为 PROPAGATION_REQUIRED 
      */ 
     void methodA() { 
         ServiceB.methodB(); 
     } 
  
} 
  
ServiceB { 
       
     /** 
      * 事务属性配置为 PROPAGATION_REQUIRED 
      */ 
     void methodB() { 
     } 
       
} 
*************************************************

***************************************** 
ServiceA { 

/** 
* 事务属性配置为 PROPAGATION_REQUIRED 
*/ 
void methodA() { 
try { 
//savepoint 

ServiceB.methodB(); //PROPAGATION_NESTED 级别 

} catch (SomeException) { 
// 执行其他业务, 如 ServiceC.methodC(); 

} 
} 

} 
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