Spring boot integration test injecting mock object via autowire

I am using spring boot with java based configurations. I have following classes structure

@Service
public class Service implements IService{
    @autowire
    private IProcessor processor;

    public void perform(Parameter param){
        processor.process(param);
    }
}

@Service
public class Processor implements IProcessor {
    @autowire
    private ProxyFactory factory;

    public void process(Parameter param){
        final ExternalSysProxy proxy = factory.get(param.getValue(), param.getId());
        proxy.call();
    }
}

@Repository
public class ProxyFactory {
    public Proxy get(String value, String id){
        final ExternalSysProxy proxy = new proxy(value, id);
        return proxy;
    }
}

The proxy object here makes call to external system. I want to write integration test by mocking proxy object. Can you please give me some guidance how I can inject mock proxy object in this structure.