使用Spring从Properties文件加载嵌套占位符 [英] Loading Nested Placeholders from Properties File with Spring

问题描述

是否可以从属性文件中加载嵌套占位符？我正在尝试动态加载URL。

Is it possible to load nested placeholders from within a properties file? I am trying to load a URL dynamically.

例如，如果我的属性文件包含

For instance, if my properties file contains

my.url=http://localhost:8888/service/{nestedProperty}/

有没有办法在运行时加载{nestedProperty}的值？类似于ResourceBundle的行为。如果是这样，我将如何有效地实例化String？到目前为止我正在考虑

Is there a way to load in values for {nestedProperty} at runtime? Similar to the behavior of a ResourceBundle. If so, how would would I be able to effectively instantiate the String? So far I'm thinking

<bean id="myURLString" class="java.lang.String" scope="prototype" lazy-init="true">
    <property name="URL" value="${my.url}" />
</bean>

...但我不确定要嵌套的属性。如果可能的话，我想使用Annotations获取bean，尽管我目前有一些东西

...but I'm not sure what properties to nest. I'd like to get a bean using Annotations if possible, although I currently have something along the lines of

ctx.getBean("myURLString", String.class, new Object[] { nestedProperty} );

我在这里查看了PropertyPlaceholderConfigurer和其他几个属性文件问题，但我似乎无法理解弄清楚这是否可行。

I've looked into PropertyPlaceholderConfigurer and several other properties file questions on here, but I can't seem to figure out if this is even possible.

我还应该注意，我想从我的代码中动态加载这个嵌套属性，或者至少从那里操作它们（可能通过@PostConstruct？）

I should also note that I want to load this nested property dynamically from within my code, or at least manipulate them from there (possibly via @PostConstruct?)

推荐答案

是的可能：

my.url=http://localhost:8888/service/${nestedProperty}
nestedProperty=foo/bar/baz

在示例中添加大括号前面的美元符号并设置好！

Add in the dollar sign in front of the braces in your example and you're set!

要实际使用完全解析的属性，请执行以下操作：

To actually use the fully resolved property, do this:

@Value("${my.url}")
private String url;

Spring bean中的

。

in a Spring bean.

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