插件 Class 的依赖注入

Question

I have a class in a jar file like

Class A {
  B b;
  C c;
//setter based injection
}

Now I want to create a bean of A in a different project. But I don't have any main class to configure the Spring application. I have a plugin in my pom.xml which calls Class D in my project. If I create a bean with the new keyword all the autowired beans in the jar will not be available. please suggest any methods to do this.

Note: This is a Spring application, Not Spring boot.

Answer 1

So that you are able to autowire a bean you need to register that bean as a Spring-managed bean. You can do that in multiple ways, being the following ones the simplest ones:

1) @Component annotation

If you annotate A with @Component Spring will create an instance of the class and register it as a Spring-managed bean:

@Component
Class A {
  B b;
  C c;
//setter based injection
}

2) @Bean annotation

Another way to register a Bean is using a Configuration class and the @Bean annotation:

@Configuration
public class AppConfig {
    @Bean
    public A a() {
        return new A();
    }
}

If I understood correctly your use case, you will need to use option 2).