public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

System.err.println(request.getParameter("totalFee"));

String  totalFee = request.getParameter("totalFee");

// 实例化客户端

AlipayClient alipayClient = new DefaultAlipayClient("https://openapi.alipay.com/gateway.do", APP_ID,

APP_PRIVATE_KEY, "json", CHARSET, ALIPAY_PUBLIC_KEY, "RSA2");

// 实例化具体API对应的request类,类名称和接口名称对应,当前调用接口名称：alipay.trade.app.pay

AlipayTradeAppPayRequest alipayrequest = new AlipayTradeAppPayRequest();

// SDK已经封装掉了公共参数，这里只需要传入业务参数。以下方法为sdk的model入参方式(model和biz_content同时存在的情况下取biz_content)。

AlipayTradeAppPayModel model = new AlipayTradeAppPayModel();

model.setBody("商品描述");//商品描述

model.setSubject("商品描述");//商品描述

model.setOutTradeNo(getOutTradeNo());//订单号

model.setTimeoutExpress("30m");//超时时间

model.setTotalAmount(totalFee);//金额

model.setProductCode("QUICK_MSECURITY_PAY");

alipayrequest.setBizModel(model);

alipayrequest.setNotifyUrl("http://xxx.com/AliPayNotify"); //异步通知地址

try {

// 这里和普通的接口调用不同，使用的是sdkExecute

AlipayTradeAppPayResponse alipayresponse = alipayClient.sdkExecute(alipayrequest);

System.out.println(alipayresponse.getBody());// 就是orderString

// 可以直接给客户端请求，无需再做处理。

response.getWriter().append(alipayresponse.getBody()).append(request.getContextPath());

} catch (AlipayApiException e) {

e.printStackTrace();

}

}

/**

* 要求外部订单号必须唯一。

*

* @return

*/

private static String getOutTradeNo() {

SimpleDateFormat format = new SimpleDateFormat("MMddHHmmss", Locale.getDefault());

Date date = new Date();

String key = format.format(date);

Random r = new Random();

key = key + r.nextInt();

key = key.substring(0, 15);

return key;

}