java实现在SSM下使用支付宝扫码支付功能

package com.alipay.config;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ResourceBundle;
/* *
 *类名：AlipayConfig
 *功能：基础配置类
 *详细：设置帐户有关信息及返回路径
 *修改日期：2017-04-05
 *说明：
 *以下代码只是为了方便商户测试而提供的样例代码，商户可以根据自己网站的需要，按照技术文档编写,并非一定要使用该代码。
 *该代码仅供学习和研究支付宝接口使用，只是提供一个参考。
 */
public class AlipayConfig {
  //↓↓↓↓↓↓↓↓↓↓请在这里配置您的基本信息
    // 应用ID,您的APPID，收款账号既是您的APPID对应支付宝账号
    public static String app_id = "2016080403162340";
    // 商户私钥，您的PKCS8格式RSA2私钥
    public static String merchant_private_key = "MIIEvAID2tulSSmawG5+F4NZbexpnxi8NKQJPZEeAA==";
    // 支付宝公钥,查看地址：https://openhome.alipay.com/platform/keyManage.htm 对应APPID下的支付宝公钥。
    public static String alipay_public_key = "MIIBIjt26tLTKar8S1ERDWI25viBcMz7PLMxVVUmHf5tdBWfbMhUs3QIDAQAB";
    // 服务器异步通知页面路径 需http://格式的完整路径，不能加?id=123这类自定义参数，必须外网可以正常访问
    public static String notify_url = "http://localhost:8080/alipay.trade.page.pay-JAVA-UTF-8/notify_url.jsp";
    // 页面跳转同步通知页面路径 需http://格式的完整路径，不能加?id=123这类自定义参数，必须外网可以正常访问
    public static String return_url = "http://localhost:8080/Exam/index/gouMai";
    // 签名方式
    public static String sign_type = "RSA2";
    // 字符编码格式
    public static String charset = "utf-8";
    // 支付宝网关
    public static String gatewayUrl = "https://openapi.alipaydev.com/gateway.do";
    // 支付宝网关
    public static String log_path = "E:\\";
  //↑↑↑↑↑↑↑↑↑↑请在这里配置您的基本信息
    /** 
     * 写日志，方便测试（看网站需求，也可以改成把记录存入数据库）
     * @param sWord 要写入日志里的文本内容
     */
    public static void logResult(String sWord ) {
      FileWriter writer = null;
      try {
        writer = new FileWriter(log_path + "alipay_log_" + System.currentTimeMillis()+".txt");
        writer.write(sWord);
      } catch (Exception e) {
        e.printStackTrace();
      } finally { 
        if (writer != null) {
          try {
            writer.close();
          } catch (IOException e) {
            e.printStackTrace();
          }
        }
      }
    }
}

//生成有二维码，可供扫码支付的页面
  @RequestMapping(value = "aliPay")
  public String aliPay(HttpServletResponse response,ModelMap map,String chapterId,HttpServletRequest request,
      String WIDout_trade_no,String WIDtotal_amount,String WIDsubject,String WIDbody) throws IOException, AlipayApiException{
//   String a,String urlName,String couName....+"&a="+a+"&urlName="+urlName+"&couName="+couName
    //获得初始化的AlipayClient
    AlipayClient alipayClient = new DefaultAlipayClient(AlipayConfig.gatewayUrl, AlipayConfig.app_id, AlipayConfig.merchant_private_key, "json", AlipayConfig.charset, AlipayConfig.alipay_public_key, AlipayConfig.sign_type);
    //设置请求参数
    AlipayTradePagePayRequest alipayRequest = new AlipayTradePagePayRequest();
    alipayRequest.setReturnUrl(AlipayConfig.return_url+"?chapterId="+chapterId);
    alipayRequest.setNotifyUrl(AlipayConfig.notify_url);
    //付款ID，必填
    String out_trade_no = WIDout_trade_no;
    //付款金额，必填
    String total_amount = WIDtotal_amount;
    total_amount=URLDecoder.decode(total_amount,"UTF-8");//转码
    //订单名称，必填
    String subject = WIDsubject;
    subject=URLDecoder.decode(subject,"UTF-8");
    //商品描述，可空
    String body = WIDbody;
    alipayRequest.setBizContent("{\"out_trade_no\":\""+ out_trade_no +"\"," 
        + "\"total_amount\":\""+ total_amount +"\"," 
        + "\"subject\":\""+ subject +"\"," 
        + "\"body\":\""+ body +"\"," 
        + "\"timeout_express\":\"1m\"," 
        + "\"product_code\":\"FAST_INSTANT_TRADE_PAY\"}");
    //请求
    String result = alipayClient.pageExecute(alipayRequest).getBody();
     response.setContentType("text/html; charset=utf-8"); 
      PrintWriter out = response.getWriter();  
      out.println(result);  
      return null;
  }

//点击购买，将课程存入购买表中
  @RequestMapping(value="gouMai")
  @ResponseBody
  public ModelAndView gouMai(String chapterId,HttpServletRequest req,String a,String urlName,String couName,ModelMap map){
    ModelAndView mav = new ModelAndView();
    Map<String,String> mapp1 = new HashMap<String,String>();
//   SysUserTab login_user = sysuserService.getSysUserById(userId);
    HttpSession session = req.getSession();
    SysUserTab login_user1 = (SysUserTab) session.getAttribute("login_user");
    String userId = login_user1.getUserId();
//   session.setAttribute("login_user", login_user);
    mapp1.put("userId", userId);
    mapp1.put("chapterId", chapterId);
    int num = sysBuyService.getBuyCount(mapp1);
    if(num==0){
      mapp1.put("buyId", UUID.randomUUID().toString().replace("-", ""));
      sysBuyService.insertBuy(mapp1);
    }
    //查询课程内容
//   String fanhui = showFH(req,chapterId,urlName,couName,map, a);
    mav.setViewName("jsp/pay/paySuccess");
    return mav;
  }