如何强制弹簧容器不返回bean的单例实例？ [英] How do I force a spring container not to return a singleton instance of a bean?

问题描述

当我在 BeanFactory 上调用 getBean（name）时，我得到了一个定义的bean实例应用程序上下文。但是，当我再次调用 getBean（name）（具有相同的名称）时，我得到了相同的bean实例。我理解在一些（很多？）情况下这是多么可取，但是如何告诉 BeanFactory 给我一个新实例？

When I call getBean(name) on a BeanFactory, I get back an instance of the bean defined in the application context. However, when I call getBean(name) again (with the same name,) I get the same instance of the bean back. I understand how this would be desirable in some (many?) cases, but how do I tell the BeanFactory to give me a new instance?

示例Spring配置（简洁地说......我遗漏了一些冗长的内容，但这应该得到重点）：

Example Spring configuration (tersely...I've left out some verbosity, but this should get the point across):

<beans>
   <bean id="beanA" class="misc.BeanClass"/>
</beans>

示例Java：

for(int i = 0;i++;i<=1) {
    ApplicationContext context = ClassPathXmlApplicationContext("context.xml");
    Object o = context.getBean("beanA");

    System.out.println(o.toString());  // Note: misc.BeanA does not implement 
                                       // toString(), so this will display the OOID
                                       // so that we can tell if it's the same
                                       // instance
}

当我运行这个时，我会得到类似的结果：

When I run this, I get something like:

misc.BeanClass@139894
misc.BeanClass@139894

请注意，两者都有相同的OOID ...所以这些是相同的实例...但我想要不同的实例。

Note that both have the same OOID...so these are the same instances...but I wanted different instances.

推荐答案

你需要告诉spring你想要一个原型bean而不是一个单例bean

You need to tell spring that you want a prototype bean rather than a singleton bean

<bean id="beanA" class="misc.BeanClass" scope="prototype"/>

这将为您提供每个请求的新实例。

This will get you a new instance with each request.

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