Question

我创建了下面的类和接口但是没有调用原型bean构造函数。我正在使用@Lookup来创建原型范围的bean。

public interface IProtoTypeBean {}

@Component
@Scope(value = "prototype")
public class ProtoTypeBean implements IProtoTypeBean {

    public ProtoTypeBean() {
        super();
        System.out.println("ProtoTypeBean");
    }
}

@Component
public class SingleTonBean {

    IProtoTypeBean protoTypeBean = getProtoTypeBean();

    @Lookup
    public ProtoTypeBean getProtoTypeBean(){
        return null;
    }

    public static void main(String[] args) {
        ApplicationContext ctx = new AnnotationConfigApplicationContext(SingleTonBean.class);
        SingleTonBean s1 = ctx.getBean(SingleTonBean.class);
        IProtoTypeBean p1 = s1.protoTypeBean;
        SingleTonBean s2 = ctx.getBean(SingleTonBean.class);
        IProtoTypeBean p2 = s2.protoTypeBean;
        System.out.println("singelton beans " + (s1 == s2));

        // if ProtoTypeBean constructor getting called 2 times means diff objects are getting created
    }

}

Answer 1

将您的代码更改为以下步骤

 @Component("protoBean")
@Scope(value = "prototype") public class ProtoTypeBean implements IProtoTypeBean {

和

@Lookup(value="protoBean")
public abstract ProtoTypeBean getProtoTypeBean();

Answer 2

我建议使用原型提供程序。

添加maven依赖

    <dependency>
        <groupId>javax.inject</groupId>
        <artifactId>javax.inject</artifactId>
        <version>1</version>
    </dependency>

然后提及由Spring管理的两个类

ApplicationContext ctx = new AnnotationConfigApplicationContext(SingleTonBean.class, ProtoTypeBean.class);

这是提供者用法

    @Component
    public class SingleTonBean {

    @Autowired
    private Provider<IProtoTypeBean> protoTypeBeanProvider;

    public IProtoTypeBean getProtoTypeBean() {
        return protoTypeBeanProvider.get();
    }

     public static void main(String[] args) {
        ApplicationContext ctx = new AnnotationConfigApplicationContext(SingleTonBean.class, ProtoTypeBean.class);
        SingleTonBean s1 = ctx.getBean(SingleTonBean.class);
        IProtoTypeBean p1 = s1.getProtoTypeBean();
        SingleTonBean s2 = ctx.getBean(SingleTonBean.class);
        IProtoTypeBean p2 = s2.getProtoTypeBean();
        System.out.println("singleton beans " + (s1 == s2));
        System.out.println("prototype beans " + (p1 == p2));
    }
}

无法使用@Lookup注释在单例bean中的原型范围内自动装配bean

2 个答案: