为什么不在普通Java文件中调用InitializingBean的方法

Question

Let's say in my java class I have

class myClass{
  public static void main ..{
    Validator validator;
    LocalValidatorFactoryBean localValidatorFactory = new LocalValidatorFactoryBean();
    validator = localValidatorFactory.getValidator();
  }

On the last line I get nullPointerException. That is because in my localValidatorFactory, ValidatorFactory attribute is null and I guess that is responsible to get me the validator.

Now, my question is that if this was a dynamic webproject and I had a context file, wherein I had defined all these classes, then in that case it would work. Because in that case the afterPropertiesSet method is called that sets the properties, I guess.

But why is it not working in this case? And what can I do to make it work?

Is it that, I should have contextFile, that has all this thing, and in my java file, I do ApplicationContext.getBean() and after such steps, it will work? Does it mean that initializingBean will work only when things are done like this? In normal java code, I can not make initializingBean work?

Answer 1

InitializingBean and FactoryBean (ie LocalValidatorFactoryBean ) are callback interfaces of the spring framework but your code is not using it.

LocalValidatorFactoryBean may define dependencies to be autowired (ie resolved and injected) by the container but you create the instance yourself so there is no way for Spring to be involved and process those callbacks properly.

You could make all this work propperly in "normal java code" but calling the setter of the factory bean and afterPropertiesSet yourself. In that case, you're basically doing what Spring does automatically for you when LocalValidatorFactoryBean is a Spring managed bean.