Spring - 注入2个相同类型的bean [英] Spring -- inject 2 beans of same type

问题描述

我喜欢基于构造函数的注入，因为它允许我创建注入的字段 final 。我也喜欢注释驱动注入，因为它简化了我的 context.xml 。我可以用 @Autowired 标记我的构造函数，一切正常，只要我没有两个相同类型的参数。例如，我有一个类：

I like constructor-based injection as it allows me to make injected fields final. I also like annotation driven injection as it simplifies my context.xml. I can mark my constructor with @Autowired and everything works fine, as long as I don't have two parameters of the same type. For example, I have a class:

@Component
public class SomeClass {
    @Autowired(required=true)
    public SomeClass(OtherClass bean1, OtherClass bean2) {
        …
    }
}

和应用程序上下文：

<bean id="bean1" class="OtherClass" />
<bean id="bean2" class="OtherClass" />

应该有一种方法在类 SomeClass ，但我在文档中找不到它。是否有可能，或者我是否仍在梦想一个尚不存在的解决方案？

There should be a way to specify the bean ID on the constructor of the class SomeClass, but I can't find it in the documentation. Is it possible, or am I dreaming of a solution that does not exist yet?

推荐答案

@Autowired 是by-type（在这种情况下）;按照示例 @Qualifier 按名称自动装配beans.htmlrel =noreferrer>来自spring docs ：

@Autowired is by-type (in this case); use @Qualifier to autowire by-name, following the example from spring docs:

public SomeClass(
    @Qualifier("bean1") OtherClass bean1, 
    @Qualifier("bean2") OtherClass bean2) {
    ...
}

注意：与@Autowired相比，它适用于字段，构造函数和多参数方法（允许缩小通过限定符注释）参数级别），仅对具有单个参数的字段和bean属性setter方法支持@Resource。因此，如果您的注入目标是构造函数或多参数方法，请坚持使用限定符。

Note: In contrast to @Autowired which is applicable to fields, constructors and multi-argument methods (allowing for narrowing through qualifier annotations at the parameter level), @Resource is only supported for fields and bean property setter methods with a single argument. As a consequence, stick with qualifiers if your injection target is a constructor or a multi-argument method.

（在该文本下面是完整示例）

(below that text is the full example)

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