java Spring：将资源作为 InputStream 注入到工厂方法中
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Spring: Injecting Resource as InputStream into a factory-method
提问by nebenmir
I want to use anti-samy from OWASP. They got a Policy object, that is instantiated via a factory method.
我想使用来自 OWASP 的 anti-samy。他们得到了一个 Policy 对象，它是通过工厂方法实例化的。
public static Policy getInstance(InputStream inputStream);
The InputStream that needs to be passed to the factory-method represents the config file for the policy-object.
需要传递给工厂方法的 InputStream 表示策略对象的配置文件。
Is it possible to use create a policy bean in an spring xml context config? I know, that there is a Resource object, that can load files from classpath. But what I need is to make a InputStream out of that Resource object. Can I doe this directly in the xml-spring-context? Or do I need to write java code in order to get the InputStream?
是否可以在 spring xml 上下文配置中使用创建策略 bean？我知道，有一个 Resource 对象，可以从类路径加载文件。但是我需要的是从那个 Resource 对象中创建一个 InputStream 。我可以直接在 xml-spring-context 中这样做吗？或者我是否需要编写java代码才能获得InputStream？
回答by Sean Patrick Floyd
Use the factory-method approach together with a constructor-arg (that will be mapped to a factory method argument) and automatically converted to an InputStream from a resource notation.
将工厂方法方法与构造函数参数（将映射到工厂方法参数）一起使用，并从资源符号自动转换为 InputStream。
<bean id="policy" class="org.owasp.validator.html.Policy"
factory-method="getInstance">
<!-- type needed because there is also a getInstance(String) method -->
<constructor-arg
value="classpath:path/to/policyFile.xml"
type="java.io.InputStream" />
</bean>
See the following parts of the Spring Reference:
请参阅Spring 参考的以下部分：
- Instantiation with a static factory method
- Built-in Property Editors(InputStreamEditoris relevant here)
- Examples of Dependency Injection(last section is about
constructor-argused in the context of a staticfactory-method)
- 使用静态工厂方法实例化
- 内置属性编辑器（此处与InputStreamEditor相关）
- 依赖注入的例子（最后一节是关于
constructor-arg在静态上下文中使用的factory-method）
回答by skaffman
@seanizer's solution would be a good one if Policyclosed the InputStreamafter it was finished reading from it, but apparently it doesn't. This will result in a leak, the severity of which depends how often it is called, and the nature of the resource.
@seanizer 的解决方案如果在完成阅读后Policy关闭InputStream它会是一个很好的解决方案，但显然它没有。这将导致泄漏，泄漏的严重程度取决于调用的频率以及资源的性质。
To be safe, you should consider writing a custom FactoryBeanimplementationinstead, which handles the opening and closing of the InputStreamsafely. The FactoryBeanwould be injected with a Resourceobject.
为了安全起见，您应该考虑编写一个自定义FactoryBean实现，它可以InputStream安全地处理打开和关闭。该FactoryBean会与被注入Resource对象。
