2.7.0版本getContextPath方法：
```
protected String getContextPath(URL url) {
        String contextPath = url.getPath();
        return contextPath.endsWith("/") ? contextPath.substring(0,contextPath.length()-1) : contextPath;
    }
```
无法将方法置入web容器中，退回2.6.5版本的方法：
```
protected String getContextPath(URL url) {
        int pos = url.getPath().lastIndexOf("/");
        return pos > 0 ? url.getPath().substring(0, pos) : "";
    }
```
使用正常，两个方法应该不等价的。
logger.warn(new IllegalStateException("error state, exporter should not be null"));
        } else {
            final Invoker<T> invokerDelegate = new InvokerDelegate<T>(originInvoker, newInvokerUrl);
            exporter.setExporter(protocol.export(invokerDelegate));
        }
        return exporter;
    }
    /**
     * Get an instance of registry based on the address of invoker
     *
     * @param originInvoker
     * @return
     */
    private Registry getRegistry(final Invoker<?> originInvoker) {
        URL registryUrl = getRegistryUrl(originInvoker);
        return registryFactory.getRegistry(registryUrl);
    }
    private URL getRegistryUrl(Invoker<?> originInvoker) {
        URL registryUrl = originInvoker.getUrl();
        if (REGISTRY_PROTOCOL.equals(registryUrl.getProtocol())) {
            String protocol = registryUrl.getParameter(REGISTRY_KEY, DEFAULT_DIRECTORY);
            registryUrl = registryUrl.setProtocol(protocol).removeParameter(REGISTRY_KEY);
        }
        return registryUrl;
    }
    /**
     * Return the url that is registered to the registry and filter the url parameter once
     *
     * @param providerUrl
     * @return url to registry.