SpEL:在 bean 实例化期间获取当前 bean 名称 [英] SpEL: get current bean name during bean instantiation

问题描述

我正在尝试使用 SpEL 获取当前正在实例化的 bean 的名称，以允许使用 @PropertySource 提供的不同属性创建同一类的多个 bean.我希望有如下内容:

I am attempting to use SpEL to get the name of the bean currently being instantiated to allow multiple beans of same class to be created with different properties supplied by @PropertySource. I am hoping for something like the following:

public class SampleBean {
    @Value("${#{CurrentBeanName}.val}")
    private String val
}

其他豆:

public class OtherBean {

    @Autowired
    @Qualifier(name="BeanA")
    SampleBean beanA;

    @Autowired
    @Qualifier(name="BeanB")
    SampleBean beanB;
}

属性文件:

BeanA.val=VALUE A
BeanB.val=VALUE B

如果我将 beanName=BeanA 添加到我的属性文件中，我就可以使用它

If I add beanName=BeanA to my properties file, I am able to get this to work with

@Value("${${beanName}.val}")

关于如何处理 #{BeanName} 的任何想法?如果这是不可能的，那就这样吧，但如果它有效，它会比我目前的解决方案干净得多.

Any ideas on what to do for #{BeanName}? If this is impossible then so be it, but if it works it would be much cleaner than my current solution.

或者有什么方法可以将 xml bean 定义中的常量传递给 SpEL?例子:

Or any way to pass a constant from the xml bean definition to SpEL? example:

<bean id="BeanA" class="...">
    <property name="prefix" value="BeanA"/>
</bean>

Java:

public class SampleBean {
    @Value("${#{prefix}.val}")
    private String val
}

任何类型的属性或任何东西都可以使用

Any sort of attribute or anything would work

编辑 2:

这在旧的基于 XML 的配置中是微不足道的

This is trivial in old XML based config

spring.xml:

spring.xml:

<bean id="beanA" class="SampleBean">
    <property name="val" value="${BeanA.val}"/>
</bean>
<bean id="beanB" class="SampleBean">
    <property name="val" value="${BeanB.val}"/>
</bean>

SampleBean.java:

SampleBean.java:

public class SampleBean {

    private String val;

    public void setVal (String val) {
        this.val = val;
    }
}

但是，当切换到新的 @Value 注释以摆脱所有 setter 时，似乎不支持具有 diff 属性的非单例(即无法动态过滤 @值 bean 创建的参数)

However when switching to the new @Value annotations to get rid of all the setters, it seems non-singletons with diff properties aren't supported (i.e. no way to dynamically filter @Value arguments on bean creation)

推荐答案

否;无法引用当前 bean.

No; it is not possible to reference the current bean.

编辑

为了解决您在下面的评论，Java 配置等效于

To address your comment below, the Java Configuration equivalent of

<bean id="BeanA" class="com.my.Foo">
    <property name="prefix" value="BeanA"/>
</bean>

是

@Bean
public Foo BeanA() {
    Foo a = new Foo();
    a.setPrefix("BeanA");
}

尽管按照惯例，您可能会将其命名为 beanA.

although, by convention, you'd probably name it beanA.

这篇关于SpEL:在 bean 实例化期间获取当前 bean 名称的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！