java开发微信公众号支付

Z时代
2024-01-10
分类：IT

最近做了微信公众号支付的开发，由于是第一次做也摸索了几天的时间，也只是达到了实现功能的水平，并没有太多考虑到性能问题，所以这篇文章比较适合初学者。

微信公众号支付的总体其实很简单，大致就分为三步。第一步需要获取用户授权；第二步调用统一下单接口获取预支付id；第三步H5调起微信支付的内置的js。下面介绍具体每一步的开发流程。

一首先要明确微信公众号支付属于网页版支付，所以相较于app的直接调取微信支付要多一步微信授权。也就是需要获取用户的openid。微信公众号使用的交易类型是JSAPI，所以统一下单接口的文档明确的写到

因此我们必须去获取openid，同时也可以处理一些我们需要的逻辑。获取用户授权有两种方式:1.scope=snsapi_base;2.scope=snsapi_userinfo.我使用的是snsapi_base

Scope为snsapi_base

https://open.weixin.qq.com/connect/oauth2/authorize?appid=wx520c15f417810387&redirect_uri=http%3A%2F%2Fchong.qq.com%2Fphp%2Findex.php%3Fd%3D%26c%3DwxAdapter%26m%3DmobileDeal%26showwxpaytitle%3D1%26vb2ctag%3D4_2030_5_1194_60&response_type=code&scope=snsapi_base&state=123#wechat_redirect

Scope为snsapi_userinfo

https://open.weixin.qq.com/connect/oauth2/authorize?appid=wxf0e81c3bee622d60&redirect_uri=http%3A%2F%2Fnba.bluewebgame.com%2Foauth_response.php&response_type=code&scope=snsapi_userinfo&state=STATE#wechat_redirect

微信的官方文档也有对各个参数的详细说明，我就关键的参数仔细的说明一下。首先appid就不多说了就是你微信公众号的appid固定写死的，redirect_uri这个参数是最重要的，这个地址是访问你处理的接口地址。你可以在这个链接上拼接上你所需要的参数，一般你是要把订单的金额传到这个接口里的，访问这个链接的时候微信会给你code你需要用它去获取openid，记得要对其进行urlencode处理。state参数可以理解为扩展字段，其他的参数都是固定写法就不在多做介绍了。下面是获取openid的代码片段。


//获取openId
            HttpClientUtil util = HttpClientUtil.getInstance();
            Map<String, String> map = new HashMap<String, String>();
            map.put("appid", WxPayConfig.APPID);
            map.put("secret", WxPayConfig.APPSECRET);
            map.put("code", code);
            map.put("grant_type", WxPayConfig.GRANT_TYPE);
            String returnStr = util.doPostRetString("https://api.weixin.qq.com/sns/oauth2/access_token", null,map);
            logger.info("returnStr:[" + returnStr + "]");
            AccessToken at = JSON.parseObject(returnStr, AccessToken.class);

AccessToken.java


public class AccessToken {
  private String access_token;
  private String expires_in;
  private String refresh_token;
  private String openid;
  private String scope;
  private String unionid;
  public String getAccess_token() {
    return access_token;
  }
  public void setAccess_token(String access_token) {
    this.access_token = access_token;
  }
  public String getExpires_in() {
    return expires_in;
  }
  public void setExpires_in(String expires_in) {
    this.expires_in = expires_in;
  }
  public String getRefresh_token() {
    return refresh_token;
  }
  public void setRefresh_token(String refresh_token) {
    this.refresh_token = refresh_token;
  }
  public String getOpenid() {
    return openid;
  }
  public void setOpenid(String openid) {
    this.openid = openid;
  }
  public String getScope() {
    return scope;
  }
  public void setScope(String scope) {
    this.scope = scope;
  }
  public String getUnionid() {
    return unionid;
  }
  public void setUnionid(String unionid) {
    this.unionid = unionid;
  }
  @Override
  public String toString() {
    return "AccessToken [access_token=" + access_token + ", expires_in="
        + expires_in + ", refresh_token=" + refresh_token + ", openid="
        + openid + ", scope=" + scope + ", unionid=" + unionid + "]";
  }
}

二我们获取了openid后，就可以进行下一步的统一下单的开发了。微信上统一下单接口的文档写的比较详细了，具体的参数含义我就不多做介绍了。下面直接贴最直观的代码，特别提醒的是一定要注意签名的正确。签名所使用的key并不是AppSecret而是你申请时自己定义的商户key。


//统一下单
            WxPaySendData data = new WxPaySendData();
            data.setAppid(WxPayConfig.APPID);
            data.setAttach("微信支付");
            data.setBody("微信公众号支付");
            data.setMch_id(WxPayConfig.MCHID);
            data.setNonce_str(nonceStr);
            data.setNotify_url(WxPayConfig.NOTIFY_URL);
            data.setOut_trade_no(tradeNo);
            data.setTotal_fee((int)(fee*100));//单位：分
            data.setTrade_type("JSAPI");
            data.setSpbill_create_ip(ip);
            data.setOpenid(at.getOpenid());
            String returnXml = UnifiedorderService.unifiedOrder(data,WxPayConfig.KEY);
            WxPayReturnData reData = new WxPayReturnData();
            XStream xs1 = new XStream(new DomDriver());
            xs1.alias("xml", WxPayReturnData.class);
            reData = (WxPayReturnData) xs1.fromXML(returnXml);

UnifiedorderService.java


public class UnifiedorderService {
  private final static Logger logger = LoggerFactory.getLogger(UnifiedorderService.class);
  public static String unifiedOrder(WxPaySendData data,String key){
    //统一下单支付
    String returnXml = null;
    try {
      //生成sign签名
      SortedMap<Object,Object> parameters = new TreeMap<Object,Object>();
      parameters.put("appid", data.getAppid()); 
      parameters.put("attach", data.getAttach());
      parameters.put("body", data.getBody());
      parameters.put("mch_id", data.getMch_id());
      parameters.put("nonce_str", data.getNonce_str());
      parameters.put("notify_url", data.getNotify_url());
      parameters.put("out_trade_no", data.getOut_trade_no());
      parameters.put("total_fee", data.getTotal_fee());
      parameters.put("trade_type", data.getTrade_type());
      parameters.put("spbill_create_ip", data.getSpbill_create_ip());
      parameters.put("openid", data.getOpenid());
      parameters.put("device_info", data.getDevice_info());
      logger.info("SIGN:"+WxSign.createSign(parameters,key));
      data.setSign(WxSign.createSign(parameters,key));
      XStream xs = new XStream(new DomDriver("UTF-8",new XmlFriendlyNameCoder("-_", "_")));
      xs.alias("xml", WxPaySendData.class);
      String xml = xs.toXML(data);
      logger.info("统一下单xml为:\n" + xml);
      HttpClientUtil util = HttpClientUtil.getInstance();
      returnXml = util.doPostForString("https://api.mch.weixin.qq.com/pay/unifiedorder", null, xml);
      logger.info("返回结果:" + returnXml);
    } catch (Exception e) {
      e.printStackTrace();
    } 
    return returnXml;
  }
}

WxSign


public class WxSign {
  private static String characterEncoding = "UTF-8";
  @SuppressWarnings("rawtypes")
  public static String createSign(SortedMap<Object,Object> parameters,String key){ 
    StringBuffer sb = new StringBuffer(); 
    Set es = parameters.entrySet();//所有参与传参的参数按照accsii排序（升序） 
    Iterator it = es.iterator(); 
    while(it.hasNext()) { 
      Map.Entry entry = (Map.Entry)it.next(); 
      String k = (String)entry.getKey(); 
      Object v = entry.getValue(); 
      if(null != v && !"".equals(v)  
          && !"sign".equals(k) && !"key".equals(k)) { 
        sb.append(k + "=" + v + "&"); 
      } 
    } 
    sb.append("key=" + key);
    String sign = MD5Util.MD5Encode(sb.toString(), characterEncoding).toUpperCase(); 
    return sign; 
  }
  public static String getNonceStr() {
    Random random = new Random();
    return MD5Util.MD5Encode(String.valueOf(random.nextInt(10000)), "UTF-8");
  }
  public static String getTimeStamp() {
    return String.valueOf(System.currentTimeMillis() / 1000);
  }
}

最后要提一下的是NOTIFY_URL回调地址，接收微信支付异步通知回调地址。

三通过上面的操作我们获得了预支付交易会话标识prepay_id，这样我们就可以进行最后一步的操作了。使用H5调起支付api。


//H5调起支付
              attr.addAttribute("appId", reData.getAppid());
              attr.addAttribute("timeStamp", WxSign.getTimeStamp());
              attr.addAttribute("nonceStr", reData.getNonce_str());
              attr.addAttribute("package", "prepay_id="+reData.getPrepay_id());
              attr.addAttribute("signType", "MD5");
              SortedMap<Object,Object> signMap = new TreeMap<Object,Object>();
              signMap.put("appId", reData.getAppid()); 
              signMap.put("timeStamp", WxSign.getTimeStamp());
              signMap.put("nonceStr", reData.getNonce_str());
              signMap.put("package", "prepay_id="+reData.getPrepay_id());
              signMap.put("signType", "MD5");
              logger.info("PaySIGN:"+WxSign.createSign(signMap,WxPayConfig.KEY));
              attr.addAttribute("paySign", WxSign.createSign(signMap,WxPayConfig.KEY));

将需要的参数传给页面后，使用微信提供方法调起支付。


<script>
  function getUrlParam(name) {
    //构造一个含有目标参数的正则表达式对象 
    var reg = new RegExp("(^|&)" + name + "=([^&]*)(&|$)");
    //匹配目标参数 
    var r = window.location.search.substr(1).match(reg);
    //返回参数值 
    if (r != null)
      return unescape(r[2]);
    return null;
  }
  function onBridgeReady() {
    var appId = getUrlParam('appId');
    var timeStamp = getUrlParam('timeStamp');
    var nonceStr = getUrlParam('nonceStr');
    var Package = getUrlParam('package');
    var signType = getUrlParam('signType');
    var paySign = getUrlParam('paySign');
    WeixinJSBridge.invoke('getBrandWCPayRequest', {
      "appId" : appId,//"wx2421b1c4370ec43b", //公众号名称，由商户传入   
      "timeStamp" : timeStamp,//"1395712654", //时间戳，自1970年以来的秒数   
      "nonceStr" : nonceStr,//"e61463f8efa94090b1f366cccfbbb444", //随机串   
      "package" : Package,//"prepay_id=u802345jgfjsdfgsdg888",
      "signType" : signType,//"MD5", //微信签名方式:   
      "paySign" : paySign,//"70EA570631E4BB79628FBCA90534C63FF7FADD89" //微信签名 
    }, function(res) { // 使用以上方式判断前端返回,微信团队郑重提示：res.err_msg将在用户支付成功后返回  ok，但并不保证它绝对可靠。  
      //alert(res.err_msg);
      if (res.err_msg == "get_brand_wcpay_request:ok") {
        alert("支付成功");
      }
      if (res.err_msg == "get_brand_wcpay_request:cancel") {
        alert("交易取消");
      }
      if (res.err_msg == "get_brand_wcpay_request:fail") {
        alert("支付失败");
      }
    });
  }
  function callPay() {
    if (typeof WeixinJSBridge == "undefined") {
      if (document.addEventListener) {
        document.addEventListener('WeixinJSBridgeReady', onBridgeReady,
            false);
      } else if (document.attachEvent) {
        document.attachEvent('WeixinJSBridgeReady', onBridgeReady);
        document.attachEvent('onWeixinJSBridgeReady', onBridgeReady);
      }
    } else {
      onBridgeReady();
    }
  }
</script>