如何获取和使用瞬态实例？ [英] How to get and use a transient instance?

问题描述

我只是想在控制器中使用一个域类的临时实例。瞬态实例本质上是两个持久实例的交叉产物，我不需要或不想坚持它。但是，我仍然得到一个TransientObjectException。有没有办法实例化一个对象的一点点，只是为了方便，然后扔掉它没有坚持它？

这是grails 2.2.0。感谢！

好的，添加了一些代码：

我处理的是保修：

  class保修{
 
 // ...其他字段... 
客户端客户端
  

客户是唯一必填字段。 客户端类同样具有保证外键：

  class客户端{
 
 // ...其他字段... 
保修保修
  
 
 
 
在控制器中：
  String name = params .name 
 if（name == null）{return} 
 Client client = Client.findByClientName（name as String）
 
 ... ...其他东西... 
 
 def warranty =新保修（客户：客户）
返回//用于测试目的
  
 ...并引发异常！
解决方案
我的猜测是您修改了客户端实例，因此当您创建新的Warranty时，它会引用未保存的客户端。尝试添加 client.discard（）在创建保修期之前。
 
I'm just trying to use a transient instance of a domain class in a controller. The transient instance is essentially a cross-product of two persistent instances, and I don't need or want to persist it.  However, I am still getting a TransientObjectException.  Is there no way to instantiate an object for a little bit just for convenience and then throw it away without persisting it?

This is grails 2.2.0.  Thanks!

Okay, adding some codes:

The class in particular that I'm dealing with is Warranty:
class Warranty {

    // ...other fields...
    Client client
client is the only required field. The Client class, similarly, has a Warranty foreign key:
class Client {

    // ...other fields...
    Warranty warranty
In the controller:
String name = params.name
if (name == null) { return }
Client client = Client.findByClientName(name as String)

// ...other stuff...

def warranty = new Warranty(client: client)
return // for testing purposes
...and that raises the exception!
解决方案
My guess is that you modified your client instance, so when you create a new Warranty, it references to the unsaved client.

Try adding client.discard() before creating the warranty.

                        
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