public List<US> selectUS(){
		connectionDB();
		String sql="select userId,userName,sex,age,telphone,address,power,passWord from us";
		List<US> users=new ArrayList<US>();
     	try {
			ps=conn.prepareStatement(sql);
			rs=ps.executeQuery();
			US user=null;
			while(rs.next()){
				user=new US();
				user.setUserId(rs.getLong("userId"));
				user.setUserName(rs.getString("userName"));
				user.setSex(rs.getString("sex"));
				user.setAge(rs.getInt("age"));
				user.setTelphone(rs.getString("telphone"));
				user.setAddress(rs.getString("address"));
				user.setPower(rs.getString("power"));
				user.setPassWord(rs.getString("passWord"));
				users.add(user);
			}
			
		} catch (SQLException e) {
			e.printStackTrace();
		}finally{
			closeDB();
		}
		return users;
	}