public Worldnode getWorldnodeByID(int id){
		conn = new SQLconnect().getConnection();
		Worldnode tmp = new Worldnode();
		try {
			String sql = "select * from worlds where display = 'true' and id =" + id;
			Statement st = (Statement) conn.createStatement();    // 创建用于执行静态sql语句的Statement对象  
			ResultSet rs = st.executeQuery(sql);  // 执行查询操作的sql语句，并返回插入数据的个数  
			while (rs.next())
			{
				int world_id = rs.getInt("id");
				String name = rs.getString("name");
				String creator = rs.getString("creator");
				String creattime = rs.getString("creattime");
				tmp = new Worldnode(world_id, name,creator,creattime);
			}
			conn.close();
		} catch (Exception e) {
			e.printStackTrace();
		}
		return tmp;
	}