引用一个对象定义Spring.NET表达 [英] Spring.NET Expression that References an Object Definition

问题描述

我想引用我在Spring配置文件从表达式中定义的另一个对象。具体来说，我想填充在那里我调用一个方法，然后从该方法返回的对象上的属性表达式的值的属性。

我试过以下（名称已更改）：

<预类=郎咸平的XML prettyprint-覆盖> <属性名=NullableIntProperty
表达=＃{} Some.Object.Id获得（）NullableIntValue/>


其中， Some.Object.Id 是一个参考我在一个配置文件中定义，如其他对象：

<预类=郎咸平的XML prettyprint-覆盖> <对象ID = Some.Object.Id...>


但我的应用程序无法启动与解析异常期待冒号，发现'} 。我认为这是期待一个命名空间，但是我没有找到这个文件。

我试过几件事情，但无论我打了一个死胡同。我最初尝试的 MethodInvokingFactoryObject 和 PropertyRetrievingFactoryObject 这是我们在其他地方不可为空的类型使用，但这种组合失败对于那些实际上nullables 空由于Spring看到一个对象工厂返回空作为失败（通常是这样）

解决方案

您可以使用 @（对象ID-这里）表达式语法检索Spring上下文对象使用表达式：

<预类=郎咸平的XML prettyprint-覆盖> <属性名=NullableIntProperty
表达的影响=@（Some.Object.Id）.PropertyOnSomeObject/>


I'm trying to reference another object I've defined in a Spring config file from within an expression. Specifically, I'm trying to populate a property with the value of an expression where I call a method and then a property on the object returned from that method.
I've tried the following (names have been changed):

<property name="NullableIntProperty"
          expression="#{Some.Object.Id}.Get().NullableIntValue"/>

where Some.Object.Id is a reference to another object I have defined in a config file such as:

<object id="Some.Object.Id" ... >

but my app fails to start with the parsing exception expecting "COLON", found '}'. I think it's expecting a namespace, but I'm not finding the documentation for this.

I've tried several things, but everywhere I hit a dead end. I originally tried a combination of the MethodInvokingFactoryObject and PropertyRetrievingFactoryObject which we use in other places for non-nullable types, but this fails for nullables that are actually null since Spring sees an object factory returning null as a failure (which it usually is).

解决方案

You can use the @(object-id-here) expression syntax to retrieve an object from the Spring context using an expression:

<property name="NullableIntProperty"
          expression="@(Some.Object.Id).PropertyOnSomeObject"/>

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