public boolean loginServer(int jkNum,String pwd){
	  try{
		  MsgLogin ml=new MsgLogin();
		  ml.setTotalLen(4+1+4+4+10);
		  ml.setType(IMsgConstance.command_login);
		  ml.setDest(IMsgConstance.Server_JK_NUMBER);
		  ml.setSrc(jkNum);
		  ml.setPwd(pwd);
		  this.sendMsg(ml);
		  //˵½֮,һӦϢ
		  MsgHead loginResp=readFromServer();
		  MsgLoginResp mlr=(MsgLoginResp)loginResp;
		  return mlr.getState()==0;
		}catch(Exception ef){
			ef.printStackTrace();
		}
		return false;
	}