如何从自定义 Java 组件内的上下文属性占位符标记获取属性 [英] How to get property from context property placeholder tag inside custom java component

问题描述

我有定义

<context:property-placeholder location="classpath:/mule-sw.properties"/>

而且我还有一个 Java 中的自定义组件类，它在我的一个字段上使用 @Lookup 注释

And I also have a custom component class in Java which use @Lookup annotation on one of my field

@Lookup("file-path")
private String path;

考虑到我的mule-sw.properties"是这样的

Considering my "mule-sw.properties" is like this

file-path=C:/hello.txt

启动Mule App后，总是出现Deploy Exception

After I start up the Mule App, I always get Deploy Exception

org.mule.api.expression.RequiredValueException: "Required object not found in registry of Type "class java.lang.String" with name "file-path" on object "class component.CustomComponent"

我也尝试使用 @Lookup("${file-path}") 更改 @Lookup("file-path") ，但没有成功.

I also tried to change the @Lookup("file-path") with @Lookup("${file-path}") with no success.

谁能给我一个更好的解决方案?任何帮助表示感谢.

Anyone can give me a better solution ? Any help is kindly appreciated.

谢谢

推荐答案

@Lookup 注解旨在检索 注册表中的对象，而您要做的是为自定义组件的属性赋值.

The @Lookup annotation is designed to retrieve objects from the registry , whereas what you are trying to do is to assign a value to an attribute of your custom component.

有两种方法可以做到这一点:

There are 2 way to do that:

1) 通过属性注入，即你像下面这样声明你的组件:

1) Through property injection, i.e. you declare your component like the following:

<custom-component class="org.myCompany.CustomComponent">
    <property name="file-path" value="${file-path}" />
</custom-component>

2) 通过 Spring EL 支持和 @Value 注释，即您通过以下方式注释您的属性

2) Through Spring EL support and the @Value annotation, i.e. you annotate your attribute in the following way

@Value("${file-path}")
private String path;

我推荐第一种方法，因为从流程的角度来看它更容易维护

I'd recommend the first approach since it is easier to maintain from a flow perspective

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