Spring MVC Bean 更新（再次执行 bean）

Question

So I'm new with Spring MVC and I need to update a bean after determined action.

Example: I defined the following bean:

@Bean
public LocaleResolver localeResolver(){
    CookieLocaleResolver resolver = new CookieLocaleResolver();
    resolver.setDefaultLocale(new Locale("en"));
    return resolver;
}

After the user do the login in the system, I need to update the bean to match the language set up in his profile. So, how can I call (execute) the bean again after the login? Thanks.

Answer 1

This is not aa standard way to do handle the user's locale. I recommend storing this information in the database with the user itself as long as the characteristic is mutable and varies across multiple users.

However, one of the best ways of updating bean in runtime is using DefaultSingletonBeanRegistry which is still supported in the current version of Spring (5.2.x as far as I know). Actually, what you do is to delete the bean and register it back again with a new value.

Start with ConfigurableApplicationContext that helps you to get the DefaultSingletonBeanRegistry .

@Autowired
ConfigurableApplicationContext context;

And the code of deletion and registration of a bean should look like:

LocaleResolver localeResolver = ... // a new bean to be registered, up to you :)

DefaultSingletonBeanRegistry registry = (DefaultSingletonBeanRegistry) context.getBeanFactory();
registry.destroySingleton("localeResolver");
registry.registerSingleton("localeResolver", localeResolver);

I have never used it actually, but I have found a few examples that might be useful: Programcreek .

Important: I am worried this way will not update/refresh already registered old injected beans. I hope someone can confirm/dispute this statement.