如果我在Spring bean中的私有方法上有一个@Transactional -annotation，那么这个annotation有任何效果吗?
如果@Transactional注释位于公共方法上，则它将工作并打开事务。
public class Bean {
public void doStuff() {
doPrivateStuff();
}
@Transactional
private void doPrivateStuff() {
}
}
...
Bean bean = (Bean)appContext.getBean("bean");
bean.doStuff();
当前回答
Spring文档解释了这一点
In proxy mode (which is the default), only external method calls coming in through the proxy are intercepted. This means that self-invocation, in effect, a method within the target object calling another method of the target object, will not lead to an actual transaction at runtime even if the invoked method is marked with @Transactional. Consider the use of AspectJ mode (see mode attribute in table below) if you expect self-invocations to be wrapped with transactions as well. In this case, there will not be a proxy in the first place; instead, the target class will be weaved (that is, its byte code will be modified) in order to turn @Transactional into runtime behavior on any kind of method.
另一种方法是使用BeanSelfAware
其他回答
你的问题的答案是否定的——@Transactional如果用于注释私有方法将没有任何影响。代理生成器将忽略它们。
Spring Manual第10.5.6章记录了这一点:
方法可见性和@Transactional 在使用代理时，应该应用代理 只有@Transactional注释 到具有公共可见性的方法。如果 注释protected, private或 类的包可见方法 @事务性注释，没有错误 ，但是带注释的方法 没有显示配置 事务设置。考虑到 如果需要，可以使用AspectJ(见下面) 注释非公共方法。
如果需要在事务中包装私有方法，而不想使用AspectJ，则可以使用TransactionTemplate。
@Service
public class MyService {
@Autowired
private TransactionTemplate transactionTemplate;
private void process() {
transactionTemplate.executeWithoutResult(status -> processInTransaction());
}
private void processInTransaction(){
//...
}
}
与@loonis建议使用TransactionTemplate的方式相同，可以使用这个帮助组件(Kotlin):
@Component
class TransactionalUtils {
/**
* Execute any [block] of code (even private methods)
* as if it was effectively [Transactional]
*/
@Transactional
fun <R> executeAsTransactional(block: () -> R): R {
return block()
}
}
用法:
@Service
class SomeService(private val transactionalUtils: TransactionalUtils) {
fun foo() {
transactionalUtils.executeAsTransactional { transactionalFoo() }
}
private fun transactionalFoo() {
println("This method is executed within transaction")
}
}
不知道TransactionTemplate是否重用现有事务，但这段代码肯定会重用。
答案是否定的。请参见Spring参考:使用@Transactional ：
@Transactional注释可以放在接口定义、接口上的方法、类定义或类上的公共方法之前
默认情况下，@Transactional属性仅在对从applicationContext获得的引用调用带注释的方法时有效。
public class Bean {
public void doStuff() {
doTransactionStuff();
}
@Transactional
public void doTransactionStuff() {
}
}
这将打开一个事务:
Bean bean = (Bean)appContext.getBean("bean");
bean.doTransactionStuff();
这将不会:
Bean bean = (Bean)appContext.getBean("bean");
bean.doStuff();
Spring引用:使用@Transactional
Note: In proxy mode (which is the default), only 'external' method calls coming in through the proxy will be intercepted. This means that 'self-invocation', i.e. a method within the target object calling some other method of the target object, won't lead to an actual transaction at runtime even if the invoked method is marked with @Transactional! Consider the use of AspectJ mode (see below) if you expect self-invocations to be wrapped with transactions as well. In this case, there won't be a proxy in the first place; instead, the target class will be 'weaved' (i.e. its byte code will be modified) in order to turn @Transactional into runtime behavior on any kind of method.
