public static PageInfo getPageInfo(int pageId) {
		
		PageInfo page = null;
		
		try{
			conn = DBConnection.getConnectionInstance();
			String sql = "select url, title, saved_name, plain from page where pageid = ?";
			
			PreparedStatement preparedStatement = conn.prepareStatement(sql);
			preparedStatement.setInt(1, pageId);
			
			int cnt = 0;
			ResultSet rs = preparedStatement.executeQuery();
			page = new PageInfo();
			while(rs.next()) {
				++cnt;
				page.setUrl(rs.getString(1));
				page.setTitle(rs.getString(2));
				page.setSavedName(rs.getString(3));
				page.setPlain(rs.getString(4));
				page.setDocID(pageId);
			}
			
			if(cnt == 0)
				return null;
			
		}
		catch(Exception e) {
			
			System.out.println("get failure !");
			e.printStackTrace();
		}
		
		return page;
		
	}