I have following JPA method that fetches stream of objects

@Cacheable("accounts")
    Stream<Account> findAccounts(int branchCode, int accountCode);

	














    

		

        

            
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首页  > 解决方案 > 如何将 @Cacheable 与方法返回类型 Stream 一起使用 in Spring?

I have following JPA method that fetches stream of objects



@Cacheable("accounts")
    Stream<Account> findAccounts(int branchCode, int accountCode);












spring - 如何将 @Cacheable 与方法返回类型 Stream 一起使用 in Spring?

I have following JPA method that fetches stream of objects



@Cacheable("accounts")
    Stream<Account> findAccounts(int branchCode, int accountCode);






问题描述



I have following JPA method that fetches stream of objects



@Cacheable("accounts")
    Stream<Account> findAccounts(int branchCode, int accountCode);




Since the stream will close after calling the method therefore I am getting following error when I call the method for second time.



java.lang.IllegalStateException: stream has already been operated upon or closed




What I like to do is; cache the content of stream i.e. accounts and read from cache for all subsequent calls. 
What would be the best way to achieve this ?



UPDATE: Note that I am aware of using a List but it is required to keep return type Stream. 







How to remove notifications sent be oracle database?


I have an app that places triggers in oracle database table so that when there is a change like an insert or an update I get a notification in my program.
The app is suppose to remove those triggers after it closes but there is an error and sometimes they remain there in the database and I have no idea how to remove them since the can not remove triggers it does not know that exist.



In sqldeveloper it looks something like this:
https://imgur.com/a/5lDhPSb



How do I remove these ?
Thanks.



UPDATE:
in the morning the problem was solved by itself and the table was empty
but after running my app a few times it's again full with orphan change notifications and the program acts randomly. Sometimes I don't get any notification and sometimes I get multiple notifications for the same event in a row.



Does anyone actually know how to remove all change notifications from database using sqldeveloper or a simple program ?


标签： springspring-bootspring-data-jpajava-stream


解决方案









您不能缓存Stream. 但是，您可以缓存的是任何类型的Collection（最好是List）。



为了不破坏 API 契约，您只需提取一个返回 a 的私有方法List，并用@Cacheable. 然后，原始方法（没有@Cacheable注释）只是调用可缓存方法并对其进行调用，每次调用时都会stream()构造一个新方法，如下所示：StreamList



Stream<Account> findAccounts(int branchCode, int accountCode) {
    return findAccountList(branchCode, accountCode).stream();
}

@Cacheable("accounts")
private List<Account> findAccountList(int branchCode, int accountCode);







但是，如果您非常确定要缓存一个延迟评估的数据结构（我不推荐），您可以使用jOOλ（SeqBuffer不过它是包私有的，所以我想您只需要复制代码） .



免责声明：我是该SeqBuffer课程的作者。










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