Spring框架如何自动装配集合 [英] How does Spring framework autowire a collection

问题描述

我从未见过自动收集的集合：

I've never seen an autowired collection:

@Service
public class SomeFactory {
    @Autowired
    private List<Foo> foos;

    @PostConstruct
    public void init() {
        for(Foo foo: foos) { 
            //do something
        }
    }
}

在init（）方法中，我可以看到foos已经有几个条目。我猜Spring知道谁应该是foos的入口。但是，怎么样？如果我想将Foo对象添加到foos中，我该怎么办？需要在属性文件中配置，还是任何其他想法？

In init() method, I can see foos has several entries already. I guess Spring knows who's supposed to be the entry of foos. But, how? What should I do if I want to add a Foo object into foos? Need to configure in a property file, or any other idea?

推荐答案

Spring的BeanFactory基本上是bean的注册表。这些bean可以使用XML声明，或者使用Configuration类中的 @Bean -annotated方法声明，或者使用包扫描自动发现。

Spring's BeanFactory is basically a registry of beans. These beans can be declared using XML, or using @Bean-annotated methods in a Configuration class, or be automatically discovered using package scanning.

当你要求 List< Foo> 时，Spring会找到所有类型为Foo的bean，创建一个包含这些bean的List，然后注入list。

When you ask for a List<Foo>, Spring finds all the beans that are of type Foo, creates a List containing those beans, and injects that list.

关于Autowired的文档解释了它，BTW：

这也是可能的通过向需要该类型数组的字段或方法添加注释来提供ApplicationContext中特定类型的所有bean

It is also possible to provide all beans of a particular type from the ApplicationContext by adding the annotation to a field or method that expects an array of that type

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