Should I put my ThreadLocals in a spring-injected singleton?

Question

Several people (eg at serverside http://www.theserverside.com/news/thread.tss?thread_id=41473) suggest that using ThreadLocal objects is as bad as using global variables. I

Answer 1

If you use Spring, you can simply use a request-scoped bean instead of explicit ThreadLocals:

public interface UserName {
    ...
}

@Component 
@Scope(value = "request", proxyMode = ScopedProxyMode.INTERFACES)
public class UsernameImpl implements UserName { 
    private String username; 
    ...
}