默认遇到throw new RuntimeException(“…”);会回滚 
需要捕获的throw new Exception(“…”);不会回滚

指定回滚

@Transactional(rollbackFor=Exception.class) 
    public void methodName() {
       // 不会回滚
       throw new Exception("...");
    } 

指定不回滚

@Transactional(noRollbackFor=Exception.class)
    public ItimDaoImpl getItemDaoImpl() {
        // 会回滚
        throw new RuntimeException("注释");
    } 

如果有事务,那么加入事务,没有的话新建一个(不写的情况下)

@Transactional(propagation=Propagation.REQUIRED) 

容器不为这个方法开启事务

@Transactional(propagation=Propagation.NOT_SUPPORTED)

readOnly=true只读,不能更新,删除

@Transactional (propagation = Propagation.REQUIRED,readOnly=true) 

设置超时时间

@Transactional (propagation = Propagation.REQUIRED,timeout=30)

设置数据库隔离级别

@Transactional (propagation = Propagation.REQUIRED,isolation=Isolation.DEFAULT)