private Client(Properties config, Transferrer transferrer) {
if (config == null)
throw new NullPointerException("properties == null!");
if (transferrer == null)
throw new NullPointerException("transferrer == null!");
config = new UnmodifiableProperties(config);
this.transferrer = transferrer;
transferrer.init(this, config);
addPropertyInfo(TRANSFERRER_KEY, "传输策略",
"暂未实现传输策略动态切换,修改后不会生效!", HttpURLConnectionTransferrer.class
.getName(), ServiceUtils.getServiceClassNames(