Question

我正在学习在Spring框架中注入的bean的范围依赖性。我正在学习解决网站的范围狭窄的Bean依赖性。但是我看不到网站中说明的分辨率。我尝试使用将ApplicationContext bean注入MySingletonBean的方法来获取MyPrototypeBean的实例。但是，我看不出bean创建过程有什么区别。

@SpringBootApplication
@ComponentScan("com.learning.spring.basics.scope.proxy")
public class SpringScopeProxyApplication {
    public static void main(String...strings) throws InterruptedException {
        ApplicationContext ctx = SpringApplication.run(SpringScopeProxyApplication.class, strings);
        SingletonBean bean1=ctx.getBean(SingletonBean.class);
        /**
         * Singleton bean is wired with a proototypeBean. But since a singleton bean is created only once by the container
         *  even the autowired proptotyeBean is also created once. 
         */

        bean1.display();

        SingletonBean bean2=ctx.getBean(SingletonBean.class);
        bean2.display();
    }

}


@Component
public class SingletonBean {
    @Autowired
    // prototypeBean is of scope prototype injected into singleton bean
    private PrototypeBean prototypeBean;

    //Fix 1 - Inject ApplicationContext and make the singletonbean applicationcontextaware

    @Autowired
    private ApplicationContext applicationContext;

    public ApplicationContext getApplicationContext() {
        return applicationContext;
    }

    public void setApplicationContext(ApplicationContext applicationContext) {
        this.applicationContext = applicationContext;
    }

    public PrototypeBean getPrototypeBean() {
        return prototypeBean;
    }

    public void setPrototypeBean(PrototypeBean prototypeBean) {
        this.prototypeBean = prototypeBean;
    }


    // Fix -1 - get the prototypeBean object from applicationContext everytime the method is called
    public void display() {
        applicationContext.getBean(PrototypeBean.class).showTime();
        //prototypeBean.showTime();
    }

    PrototypeBean

package com.learning.spring.basics.scope.proxy;

import java.time.LocalDateTime;

import org.springframework.beans.factory.config.ConfigurableBeanFactory;
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Component;

@Component
@Scope(ConfigurableBeanFactory.SCOPE_PROTOTYPE)
public class PrototypeBean {

    public void showTime() {
        System.out.println("Time is "+LocalDateTime.now().toString());
    }
}

预期结果：时间戳记应该不同，因为原型作用域bean应该是新实例
实际结果：时间戳相同，没有区别

Answer 1

这不是验证SCOPE_PROTOTYPE bean的正确方法，因为showTime是一个实例方法，当您通过对象调用它时会执行该实例方法，因此您总是会得到不同的时间戳。但是我不确定您如何获得相同的时间戳，但下面是一个示例

@SpringBootApplication
@ComponentScan("com.learning.spring.basics.scope.proxy")
public class SpringScopeProxyApplication {
public static void main(String...strings) throws InterruptedException {
    ApplicationContext ctx = SpringApplication.run(SpringScopeProxyApplication.class, strings);
    SingletonBean bean1=ctx.getBean(PrototypeBean.class);
     System.out.println(bean1);

    SingletonBean bean2=ctx.getBean(PrototypeBean.class);
     System.out.println(bean2);
     }

 }

您将获得两个不同的对象引用

com.learning.spring.basics.scope.proxy.PrototypeBean@48976e6d
com.learning.spring.basics.scope.proxy.PrototypeBean@2a367e93

具有PrototypeBean依赖项的SingletonBean

1 个答案: