public String getAllByPID(Statement statement,String PID)//根据PID获取图片地址
	{
		String result = null;
		sql = "select * from Park where PID = '" + PID +"'";
		try 
		{
			ResultSet rs = statement.executeQuery(sql);
			while (rs.next()) {
				ParkClass parkClass = new ParkClass();
				parkClass.setPid(rs.getString("PID"));
				parkClass.setCity(rs.getString("city"));
				parkClass.setDistrict(rs.getString("district"));
				parkClass.setParkname(rs.getString("parkname"));
				parkClass.setTotalnumber(rs.getInt("totalnumber"));
				parkClass.setLeftnumber(rs.getInt("leftnumber"));
				parkClass.setBookable(rs.getInt("bookable"));
				parkClass.setCost(rs.getInt("cost"));
				parkClass.setParkcharge(rs.getInt("parkcharge"));
				parkClass.setPriparkcharge(rs.getInt("priparkcharge"));
				parkClass.setLongitude(rs.getDouble("longitude"));
				parkClass.setLatitude(rs.getDouble("latitude"));
				parkClass.setLocation(rs.getString("location"));
				parkClass.setIntroduction(rs.getString("introduction"));
				parkClass.setPicurl(rs.getString("pic"));
				parkList.add(parkClass);
			}
			JSONArray jsonArray = JSONArray.fromObject(parkList);
			result = jsonArray.toString();
		} 
		catch (SQLException e) 
		{
			System.out.println("Error! (from src/Fetch/Park.getPicByPID()");
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return result;
	}