自动浇铸弹簧豆 [英] Auto-cast Spring Beans

问题描述

有没有办法自动转换Spring bean到应用程序上下文XML中定义的类？我想避免把类型信息关于bean在2个地方....在xml配置文件和代码作为一个转换。

Is there a way to auto-cast Spring beans to the class defined in the application context XML? I'd like to avoid putting type information about the beans in 2 places.... in the xml configuration file and also in the code as a cast.

例如，给定此配置文件

<bean id="bean-name" class="SimpleSpringBean"  scope="prototype">
    <property name="myValue" value="simple value"></property>
</bean>

我可以调用 ApplicationContext.getBean（bean-name），以避免直接将返回类型转换为 SimpleStringBean 。我知道我也可以调用 ApplicationContext.getBean（bean-name，SimpleSpringBean.class）以避免转换本身，但我仍然有类型信息在2个地方。

Can I call ApplicationContext.getBean("bean-name") in such a way as to avoid directly casting the return type to SimpleStringBean. I know I can also call ApplicationContext.getBean("bean-name", SimpleSpringBean.class) to avoid the cast itself, but I still have the type info in 2 places.

看起来Spring可以获取类信息（ ApplicationContext.getType ），

It seems that Spring can get the class info (ApplicationContext.getType) or by getting the type from the bean itself, but no way to automatically cast the type without programmer intervention.

推荐答案

我同意Sii，你应该避免调用getBean作为尽可能多的。

I agree with Sii, you should avoid calling getBean as much as you can. Just wire your beans to classes that depends on them.

仍然，如果你有一个类保存应用程序上下文，你可以提供一个包装器通用的方法，如下面的：

Still, if you have a single class that holds the application context, you can provide a wrapper generic method like the following:

class MyContextHolder{
    ApplicationContext appContext;
    ......
    @SuppressWarnings("unchecked")
    public static <T> T getBean(String beanName)
    {
        return (T)appContext.getBean(beanName);
    }
}

Then you can call it without casting

MyClass mc = MyContextHolder.getBean("myClassBean");

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