code: protected JsonRpcResponse execute(JsonRpcRequest request) {
          if (request == null) {
              return new JsonRpcResponse(null, JsonRpcError.parseError(null));
          }
  
          String serviceName = null;
          String methodName = request.getMethod();
          int lastIndex = methodName.lastIndexOf('.');
          if (lastIndex >= 0) {
              serviceName = methodName.substring(0, lastIndex);
              methodName = methodName.substring(lastIndex + 1);
          }
  
          ServiceEntry<?> serviceEntry = serviceRegistry.getService(serviceName);
          if (serviceEntry == null) {
              return new JsonRpcResponse(null, JsonRpcError.methodNotFoundError(null));
          }
          Set<Method> methods = serviceEntry.getMethods(methodName);
          if (methods == null || methods.isEmpty()) {
              return new JsonRpcResponse(null, JsonRpcError.methodNotFoundError(null));
          }
  
          String id = request.getId();
          Node[] params = request.getParams();
          Method method = findExecutableMethod(methods, params);
          if (method == null) {
              return new JsonRpcResponse(null, JsonRpcError.invalidParamsError(null));
          }
  
          Object service = serviceEntry.getService();
          Object[] args = getParameters(method, params);
          try {
              Object invokeValue = method.invoke(service, args);
  
              if (id == null) {
                  return null;
              }
  
              Node result = jsonImpl.convert(invokeValue);
              return new JsonRpcResponse(id, result);
          } catch (Throwable t) {
              if (t instanceof InvocationTargetException) {
                  t = ((InvocationTargetException) t).getTargetException();
              }
              LOG.debug("executing error : " + method, t);
              return new JsonRpcResponse(id, JsonRpcError.serverError(2, "Server error", t));
          }
      }
docs: 处理远端的调用请求，执行相应的方法并返回执行结果。
  
  @param request
  @return 如果request为通知将返回 null