1. non-simplify mode:
```
dubbo://120.0.0.1:20880/org.apache.dubbo.demo.DemoService?key=value
```
the store path of ZK will be: `/dubbo/porg.apache.dubbo.demo.DemoService/url`

2. simplify mode:
```
dubbo://120.0.0.1:20880/org.apache.dubbo.demo.DemoService?key=value
```
the store path of ZK will be: `/dubbo/porg.apache.dubbo.demo.DemoService/url`

3. simplify mode with path specified:
```
dubbo://120.0.0.1:20880/path-value?key=value
```
the store path of ZK will be: `/dubbo/path-value/url`
/* don't destroy for now
                try {
                    ReferenceConfig.this.destroy();
                } catch (Throwable t) {
                        logger.warn("Unexpected err when destroy invoker of ReferenceConfig(" + url + ") in finalize method!", t);
                }
                */
            }
        }
    };
    public ReferenceConfig() {
    }
    public ReferenceConfig(Reference reference) {
        appendAnnotation(Reference.class, reference);
        setMethods(MethodConfig.constructMethodConfig(reference.methods()));
    }
    public URL toUrl() {
        return urls.isEmpty() ? null : urls.iterator().next();
    }
    public List<URL> toUrls() {
        return urls;
    }
    /**
     * This method should be called right after the creation of this class's instance, before any property in other config modules is used.
     * Check each config modules are created properly and override their properties if necessary.
     */
    public void checkAndUpdateSubConfigs() {
        if (StringUtils.isEmpty(interfaceName)) {
            throw new IllegalStateException("<dubbo:reference interface=\"\" /> interface not allow null!");
        }