官网的例子通过ReferenceConfigCache缓存ReferenceConfig实例,

```java
ReferenceConfigCache cache = ReferenceConfigCache.getCache();  
// cache.get方法中会缓存 Reference对象，并且调用ReferenceConfig.get方法启动ReferenceConfig
XxxService xxxService = cache.get(reference);
```

源码中cache.get()的实现是先get, 如果== null 再put ReferenceConfig实例, 而没有提供可以由用户判断cache是否已存在的api, 我在通过groovy脚本泛化调用的时候, 需要设定当前应用与注册中心, 然后获取ReferenceConfig实例, 如下:

```java
...
// 连接注册中心配置   
RegistryConfig registry = new RegistryConfig();   
// 注册中心协议与地址   
registry.setAddress("zookeeper://127.0.0.1:2181");    
// 当前消费者应用配置  
ApplicationConfig application = new ApplicationConfig();  
application.setName("consumer-name");   
application.setRegistry(registry);  
reference.setApplication(application);   
ReferenceConfigCache referenceConfigCache = ReferenceConfigCache.getCache(); 
GenericService genericService = referenceConfigCache.get(reference);   
// 泛化调用
genericService.$invoke(XXXX);
```

每一次都会把这个脚本跑一遍, 也就是每一次都会去new RegistryConfig, 和ApplicationConfig这两个实例, 虽然除了第一次以外, ReferenceConfig都是是从原有的cache中获得; 但是并没有符合这个cache工具类的原有目的. 所以ReferenceConfigCache的get()方法能否提供单独的get()方法;
还是我的使用方式不对?
非常感谢~
if (!StringUtils.isBlank(referenceConfig.getGroup())) {
                ret.append(referenceConfig.getGroup()).append("/");
            }
            ret.append(iName);
            if (!StringUtils.isBlank(referenceConfig.getVersion())) {
                ret.append(":").append(referenceConfig.getVersion());
            }
            return ret.toString();
        }
    };
    static final ConcurrentMap<String, ReferenceConfigCache> cacheHolder = new ConcurrentHashMap<String, ReferenceConfigCache>();
    private final String name;
    private final KeyGenerator generator;
    ConcurrentMap<String, ReferenceConfig<?>> cache = new ConcurrentHashMap<String, ReferenceConfig<?>>();
    private ReferenceConfigCache(String name, KeyGenerator generator) {
        this.name = name;
        this.generator = generator;
    }
    /**
     * Get the cache use default name and {@link #DEFAULT_KEY_GENERATOR} to generate cache key.
     * Create cache if not existed yet.
     */
    public static ReferenceConfigCache getCache() {
        return getCache(DEFAULT_NAME);
    }
    /**
     * Get the cache use specified name and {@link KeyGenerator}.
     * Create cache if not existed yet.
     */
    public static ReferenceConfigCache getCache(String name) {