java实现微信支付 

package com.hk.wx.pay.service.impl;@Servicepublic class PayServiceImpl  implements PayService{  private static final Logger LOG = LoggerFactory.getLogger(PayServiceImpl.class);  private static final String PAY_URL = "https://api.mch.weixin.qq.com/pay/unifiedorder";  @Value("${appid}")  private String APPID = "";  @Value("${pay.mch_id}")  private String PAY_MACH_ID = "";  @Value("${pay.body}")  private String PAY_BODY = "";  @Value("${pay.notify_url}")  private String PAY_NOTIFY_URL = "";  @Value("${pay.trade_type}")  private String PAY_TYPR = "";  @Value("${pay.key}")  private String PAY_KEY = "";  public JSONObject wxPay(String total_fee, String imei, String ip, String openid)  {    Map pay = new LinkedHashMap();   // 按照 添加顺序 排序    pay.put("appid", this.APPID); //小程序 aapid    pay.put("attach", getOrderNum());　　//附加数据    pay.put("body", this.PAY_BODY);　　　　//商品描述    pay.put("device_info", imei);　　　　　　//    pay.put("mch_id", this.PAY_MACH_ID);　　//商品号    pay.put("nonce_str", getNonceStr());　　//随机字符串    pay.put("notify_url", this.PAY_NOTIFY_URL); //返回连接    pay.put("openid", openid);　　　　　　　　　　 //微信用户 id    pay.put("out_trade_no", getOrderNum());    //订单号    pay.put("sign_type", "MD5");    pay.put("spbill_create_ip", ip);    pay.put("total_fee", total_fee);    pay.put("trade_type", this.PAY_TYPR);    pay.put("sign", getSign(pay));    String xml = XmlUtil.mapToXMLString(pay);  // 转成 xml 形式    System.out.println(xml);    String msg = "";    try    {      msg = HttpUtils.xmlRequest("https://api.mch.weixin.qq.com/pay/unifiedorder", "POST", xml); // xml 形式 post请求      JSONObject json = XmlUtil.xmlToJSONObject(msg);      String ret = json.getString("return_code");      if ((ret != "") && (ret.equals("SUCCESS")) &&         (!"SUCCESS".equals(json.getString("result_code")))) {        return json;      }      LOG.info("# 统一下单错误...msg:" + json.toString());      return null;    }    catch (Exception e) {      LOG.error("# 支付出错...");      e.printStackTrace();    }return null;  }　　 　　 　　//获取随机数  private static String getNonceStr()  {    return Md5Utils.encryption(ComApi.getUUID());  }  //获取 sign  private static String getSign(Map
     
       parameters)  {    String characterEncoding = "UTF-8";    StringBuffer sb = new StringBuffer();    List list = new ArrayList(parameters.entrySet());    Collections.sort(list, new Comparator() {      public int compare(Map.Entry
      
        mapping1, Map.Entry
       
         mapping2) {        return ((String)mapping1.getKey()).compareTo((String)mapping2.getKey());      }    });    for (Map.Entry mapping : list) {      String k = (String)mapping.getKey();      Object v = mapping.getValue();      if ((v != null) && (!"".equals(v)) && (!"sign".equals(k)) && (!"key".equals(k))) {        sb.append(k + "=" + v + "&");      }    }    sb.append("key=key");  //key 是支付帐号里面的api安全密码    LOG.info("# sign 拼接：" + sb.toString());    String sign = Md5Utils.encryption(sb.toString(), characterEncoding).toUpperCase();    LOG.info("# 获取 签名...sign：" + sign);    return sign;  } 　 //获取订货号  private static String getOrderNum()  {    String time = TimeUtils.getSysDate("yyyyMMddHHmmssSSS");    String uuNum = ComApi.getUUNum();    String num = "HK" + time + uuNum;    return num;  }}