应用程序如何通知 Spring 应用程序上下文在哪里可以找到其构造函数带有 @Inject 注释的 class？

Question

如何修复以下示例以通知 Spring application context where to find a class Application whose constructor is annotated with @Inject，但是没有将 bean 方法引入 ApplicationConfiguration 注释为 [=17] =] returns class Application?

的实例

public class Application {
    private final A a;

    @Inject
    public Application(A a) {
        this.a = a;
    }

    public A getA() {
        return a;
    }
}

@Configuration
public class ApplicationConfiguration {
    @Bean
    public A getA() {
        return new A();
    }
}

public class A {
}

public class Start {
    public static void main(String[] arguments) {
        final ApplicationContext context = new AnnotationConfigApplicationContext(ApplicationConfiguration.class);
        final Application application = context.getBean(Application.class);
        application.getA();
    }
}

您可以在 AtInject project on GitHub 中查看源代码。

当我运行classStart,Spring抱怨找不到classApplication:

May 27, 2016 4:49:55 PM org.springframework.context.annotation.AnnotationConfigApplicationContext prepareRefresh
INFO: Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@7eda2dbb: startup date [Fri May 27 16:49:55 EDT 2016]; root of context hierarchy
May 27, 2016 4:49:55 PM org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor <init>
INFO: JSR-330 'javax.inject.Inject' annotation found and supported for autowiring
Exception in thread "main" org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.opessoftware.atinject.application.Application] is defined
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBean(DefaultListableBeanFactory.java:371)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBean(DefaultListableBeanFactory.java:331)
    at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:975)
    at com.opessoftware.atinject.start.Start.main(Start.java:11)

Answer 1

跟随 M. Deinum's , I annotated class Application with stereotype @Component to tell Spring to treat Application as a bean and annotated class ApplicationConfiguration with @ComponentScan 以指示 Spring 在哪里可以找到组件 Application:

@Component
public class Application {
    private final A a;

    @Inject
    public Application(A a) {
        this.a = a;
    }

    public A getA() {
        return a;
    }
}

@Configuration
@ComponentScan({"me.derekmahar.atinject.application", "me.derekmahar.atinject.model"})
public class ApplicationConfiguration {
    @Bean
    public A getA() {
        return new A("A1");
    }
}

请注意，我还修改了 class A 以便它接受一个名称：

public class A {
    private final String name;

    public A(String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }
}

Class Start 现在可以正确打印 "Name of a1 is "A1".":

May 30, 2016 11:14:49 AM org.springframework.context.annotation.AnnotationConfigApplicationContext prepareRefresh
INFO: Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@7eda2dbb: startup date [Mon May 30 11:14:49 EDT 2016]; root of context hierarchy
May 30, 2016 11:14:49 AM org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor <init>
INFO: JSR-330 'javax.inject.Inject' annotation found and supported for autowiring
Name of a1 is "A1".

您可以在 AtInject project on GitHub.

中找到解决方案的源代码

应用程序如何通知 Spring 应用程序上下文在哪里可以找到其构造函数带有 @Inject 注释的 class？

How can an application inform the Spring application context where to find a class whose constructor is annotated with @Inject?

java

spring

dependency-injection

jsr330