Grails 控制器类中的 HQL 查询导致 ClassCastException？
我最困惑的是。我有一个非常简单的查询。
def value = Contribution.executeQuery(
'select sum(c.balance) from Contribution c where
c.account.id=:accountId', [accountId: memberInstance?.account?.id])
我尽我所能地进行了交互式调试 - 所需的实例都不为空（memberInstance、memberInstance.account）。但产生的错误是ClassCastException？
Stacktrace follows:
java.lang.ClassCastException: com.myapp.contribution.ContributionService cannot be cast to com.myapp.contribution.ContributionService
at com.myapp.contribution.ContributionService$$FastClassByCGLIB$$d800d90.invoke(<generated>) ...
有没有人知道为什么生成 CCE，以及为什么类类型不能转换为自身（无论如何，我不明白为什么 grails 应该这样做？）
谢谢！
亚历克斯
I am most perplexed. I have a very simple query.
def value = Contribution.executeQuery(
'select sum(c.balance) from Contribution c where
c.account.id=:accountId', [accountId: memberInstance?.account?.id])
I interactively debugged as well as I could - none of the instances required are null (memberInstance, memberInstance.account). But the resulting error is a ClassCastException?
Stacktrace follows:
java.lang.ClassCastException: com.myapp.contribution.ContributionService cannot be cast to com.myapp.contribution.ContributionService
at com.myapp.contribution.ContributionService$FastClassByCGLIB$d800d90.invoke(<generated>) ...
Does anyone have any clues as to why a CCE is being generated, an furthermore, why a class type could not be cast to itself (anyway, not that I understand why grails should be doing this?)
THANK YOU!
Alexx
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好的 - 如果我将“def value”更改为“Double value”并将“[0]”附加到查询行的末尾（以获取返回的数组中的第一个值，这是缺失的部分之一），那么这作品。
CCE 非常具有误导性...
OK - if I change "def value" to "Double value" and append "[0]" to the end of the query line (to get the first value in the array returned, which was one of the missing pieces), then this works.
The CCE was very misleading...