Can you use request scoped @Context variables in a singleton ContextResolver in JAX-RS?

问题

I'm using Jersey 1.13 with Spring. I've got a ContextResolver defined like so:

@Provider
public class ThemeSourceContextResolver implements ContextResolver<ThemeSource> {

    @Context private HttpServletRequest request;

    @Override
    public ThemeSource getContext(Class<?> type) {
        return new DefaultThemeSource(request);
    }
}


<bean id="themeSourceContextResolver" scope="singleton" class="com.example.ThemeSourceContextResolver" />

Is the above valid? Specifically, is it "legal" (or does it make sense) to use the @Context private HttpServletRequest request in a ContextResolver? Since the ContextResolver is a singleton, does Jersey/JAX-RS do some threadlocal proxy magic or something to allow it to have access to the HttpServletRequest of every request?

回答1:

It's not valid. @Context is injected only into JAX-RS resources. ContextResolver<?> has nothing to do with request context, mostly because it's a singleton, as you said.

回答2:

To update this answer for Jersey 2.14:

The answer is now "sometimes". Jersey does indeed do proxy magic for specific @Context variables, namely HttpHeaders, Request, UriInfo and SecurityContext. Your specific case, HttpServletRequest, is not supported.

See https://jersey.java.net/documentation/latest/jaxrs-resources.html#d0e2578.

来源：https://stackoverflow.com/questions/13736627/can-you-use-request-scoped-context-variables-in-a-singleton-contextresolver-in