code: public static void tradePage(HttpServletResponse httpResponse, AlipayTradePagePayModel model, String notifyUrl,
  			String returnUrl) throws AlipayApiException, IOException {
  		AlipayTradePagePayRequest request = new AlipayTradePagePayRequest();
  		request.setBizModel(model);
  		request.setNotifyUrl(notifyUrl);
  		request.setReturnUrl(returnUrl);
  		String form = AliPayApiConfigKit.getAliPayApiConfig().getAlipayClient().pageExecute(request).getBody();// 调用SDK生成表单
  		httpResponse.setContentType("text/html;charset=" + AliPayApiConfigKit.getAliPayApiConfig().getCharset());
  		httpResponse.getWriter().write(form);// 直接将完整的表单html输出到页面
  		httpResponse.getWriter().flush();
  		httpResponse.getWriter().close();
  	}
docs: 电脑网站支付(PC支付)
  
  @param httpResponse
  {HttpServletResponse}
  @param model
  {AlipayTradePagePayModel}
  @param notifyUrl
  异步通知URL
  @param returnUrl
  同步通知URL
  @throws {AlipayApiException}
  @throws {IOException}