public String peekUnsearchList(){
		final String sql = "SELECT min(sn), url FROM WAIT_SEARCH_URL_WIKI";
		String sn = "";
		String url = "";
		Statement stmt;
		try {
			stmt = this.connection.createStatement();
			ResultSet rs = stmt.executeQuery(sql);
			while (rs.next()) {
				sn = rs.getString(1);
				url = rs.getString(2);
				if(sn == null || url == null){
					log.info("WAIT_SEARCH_URL_WIKI 資料用檠");
					return null;
				}
			}
			// Remove searched URI
			stmt.executeUpdate("Delete From WAIT_SEARCH_URL_WIKI Where Sn = " + sn);
			stmt.close();
		} catch (SQLException ex) {
			log.error("SQLException: " + ex.getMessage());
		}
		
		//GC
		sn = null;
		
		return url;
	}