//这个方法是核心，将会尝试建立TCP连接HTTP连接，如果都失败，抛出异常
//先尝试建立TCP连接
Transfer transfer = null;
try {
logger.debug("Try to create Tcp default transfer...");
this.activeFactory = new TcpTransferFactory();
this.activeFactory.setFetionContext(this.context);
this.activeFactory.openFactory();
transfer = this.activeFactory.createDefaultTransfer();
return transfer;
} catch (TransferException e) {