最近在研究微信小程序的支付，参考其他大神的文章，做出了订单转支付的功能
以下代码是在用户已经登录，拿到了用户的openId的情况下进行的。
基本思路：用户提交订单——后台生成订单——前台获取生成的订单号码(订单生成成功后清除购物车中该订单中的商品)——调用统一下单接口——获取统一下单接口返回的prepay_id——微信支付方法——支付判断（1.用户支付成功，显示支付成功 ，返回购物车；2.用户支付失败，提示支付失败订单已保存，返回购物车页面）
// 提交订单到后台
toPayOrder: function () {
wx.showLoading({
title: '订单提交中...',
})
var that = this;
// 校验订单中的商品库存等信息，及订单必填数据
// 提交订单到后台
// 判断邮寄地址
// 判断自取地址
// 取货时间
var orders = [];
var Ids = "";
for (var i = 0; i < this.data.goodsList.length; i++) {
// 用于订单生成后移除购物车
if (Ids == "") {
Ids = this.data.goodsList[i].Id;
} else {
Ids = Ids + "," + this.data.goodsList[i].Id
}
var goods = { "shop_goods_id": this.data.goodsList[i].ShopGoodsId, "goods_num": this.data.goodsList[i].GoodsNum };
orders.push(goods);
}
console.log(orders);
wx.request({
url: '生成订单的接口',
method: 'POST',
header: { "Authorization": "Bearer " + app.globalData.token },
data: {
// 相应参数
},
success: function (res) {
wx.hideLoading();
if (res.data.status == 200) {
// 获取订单参数
that.setData({
paySn: res.data.data
});
console.log(res);
wx.showToast({
title: '订单提交成功'
})
// 删除购物车中相应商品
if (Ids != "") {
wx.request({
url: '删除购物车接口' + Ids,
method: 'DELETE',
header: { "Authorization": "Bearer " + app.globalData.token },
success: function (res) {
console.log(res);
}
})
}
that.wxpay();
} else {
wx.showToast({
title: '提交订单失败，请稍后再试！',
icon: 'none'
})
}
}, fail: function () {
wx.hideLoading();
wx.showToast({
title: '提交订单失败，请稍后再试！',
icon: 'none'
})
}
})
},
// 微信支付方法
wxpay: function () {
var that = this;
//统一支付签名
var appid = '';//appid
var body = '';//商户名-商品描述
var mch_id = '';//商户号
var nonce_str = that.randomString();//随机字符串，不长于32位。
var notify_url = '';//通知地址,需要外网能访问
var spbill_create_ip = '';//用户端ip ，我不知道如何获取，如有知道的大神请告诉我，谢谢
var total_fee = parseFloat(this.data.afterPrice).toFixed(2) * 100;// 金额（微信支付金额是int 最小个位数对应分，所以支付金额四舍五入到小数点后两位，再乘100）
var trade_type = "JSAPI";
var key = ''; // 这个key是商户号的支付key
// 以下为获取签名的代码，为确保key的安全，在实际项目中，我们将key放在后台，由后台生成签名
var unifiedPayment = 'appid=' + appid + '&body=' + body + '&mch_id=' + mch_id + '&nonce_str=' + nonce_str + '¬ify_url=' + notify_url + '&openid=' + res.data.openid + '&out_trade_no=' + that.data.paySn + '&spbill_create_ip=' + spbill_create_ip + '&total_fee=' + total_fee + '&trade_type=' + trade_type + '&key=' + key
var sign = MD5.md5(unifiedPayment).toUpperCase();
console.log(sign)
//封装统一支付xml参数
var formData = "<xml>"
formData += "<appid>" + appid + "</appid>"
formData += "<body>" + body + "</body>"
formData += "<mch_id>" + mch_id + "</mch_id>"
formData += "<nonce_str>" + nonce_str + "</nonce_str>"
formData += "<notify_url>" + notify_url + "</notify_url>"
formData += "<openid>" + res.data.openid + "</openid>"
formData += "<out_trade_no>" + that.data.paySn + "</out_trade_no>"
formData += "<spbill_create_ip>" + spbill_create_ip + "</spbill_create_ip>"
formData += "<total_fee>" + total_fee + "</total_fee>"
formData += "<trade_type>" + trade_type + "</trade_type>"
formData += "<sign>" + sign + "</sign>"
formData += "</xml>"
//统一支付
wx.request({
url: 'https://api.mch.weixin.qq.com/pay/unifiedorder',
method: 'POST',
head: 'application/x-www-form-urlencoded',
data: formData, // 设置请求的 header
success: function (res) {
console.log(res.data)
var result_code = that.getXMLNodeValue('result_code', res.data.toString("utf-8"))
var resultCode = result_code.split('[')[2].split(']')[0]
if (resultCode == 'FAIL') {
var err_code_des = that.getXMLNodeValue('err_code_des', res.data.toString("utf-8"))
var errDes = err_code_des.split('[')[2].split(']')[0]
wx.navigateBack({
delta: 1, // 回退前 delta(默认为1) 页面
success: function (res) {
wx.showToast({
title: errDes,
icon: 'success',
duration: 2000
})
},
})
} else {
//发起支付
var prepay_id = that.getXMLNodeValue('prepay_id', res.data.toString("utf-8"))
var tmp = prepay_id.split('[')
var tmp1 = tmp[2].split(']')
//签名
var key = '';
var appId = '';
var timeStamp = that.createTimeStamp();
var nonceStr = that.randomString();
var stringSignTemp = "appId=&nonceStr=" + nonceStr + "&package=prepay_id=" + tmp1[0] + "&signType=MD5&timeStamp=" + timeStamp + "&key="
var sign = MD5.md5(stringSignTemp).toUpperCase()
console.log(sign)
var param = { "timeStamp": timeStamp, "package": 'prepay_id=' + tmp1[0], "paySign": sign, "signType": "MD5", "nonceStr": nonceStr }
that.pay(param)
}
},
})
},
fail: function () {
// fail
},
complete: function () {
// complete
}
})
},
/* 支付 */
pay: function (param) {
wx.requestPayment({
timeStamp: param.timeStamp,
nonceStr: param.nonceStr,
package: param.package,
signType: param.signType,
paySign: param.paySign,
success: function (res) {
// success
console.log(res)
wx.navigateBack({
delta: 1, // 回退前 delta(默认为1) 页面
success: function (res) {
wx.showToast({
title: '支付成功',
icon: 'success',
duration: 2000
})
},
fail: function () {
// fail
},
complete: function () {
// complete
}
})
},
fail: function () {
// fail
console.log("支付失败")
},
complete: function () {
// complete
console.log("pay complete")
}
})
}
2.添加MD5，放到utils,命名为md5.js
var rotateLeft = function(lValue, iShiftBits) {
return(lValue << iShiftBits) | (lValue >>> (32 - iShiftBits));
}
var addUnsigned = function(lX, lY) {
var lX4, lY4, lX8, lY8, lResult;
lX8 = (lX & 0x80000000);
lY8 = (lY & 0x80000000);
lX4 = (lX & 0x40000000);
lY4 = (lY & 0x40000000);
lResult = (lX & 0x3FFFFFFF) + (lY & 0x3FFFFFFF);
if(lX4 & lY4) return(lResult ^ 0x80000000 ^ lX8 ^ lY8);
if(lX4 | lY4) {
if(lResult & 0x40000000) return(lResult ^ 0xC0000000 ^ lX8 ^ lY8);
else return(lResult ^ 0x40000000 ^ lX8 ^ lY8);
} else {
return(lResult ^ lX8 ^ lY8);
}
}
var F = function(x, y, z) {
return(x & y) | ((~x) & z);
}
var G = function(x, y, z) {
return(x & z) | (y & (~z));
}
var H = function(x, y, z) {
return(x ^ y ^ z);
}
var I = function(x, y, z) {
return(y ^ (x | (~z)));
}
var FF = function(a, b, c, d, x, s, ac) {
a = addUnsigned(a, addUnsigned(addUnsigned(F(b, c, d), x), ac));
return addUnsigned(rotateLeft(a, s), b);
};
var GG = function(a, b, c, d, x, s, ac) {
a = addUnsigned(a, addUnsigned(addUnsigned(G(b, c, d), x), ac));
return addUnsigned(rotateLeft(a, s), b);
};
var HH = function(a, b, c, d, x, s, ac) {
a = addUnsigned(a, addUnsigned(addUnsigned(H(b, c, d), x), ac));
return addUnsigned(rotateLeft(a, s), b);
};
var II = function(a, b, c, d, x, s, ac) {
a = addUnsigned(a, addUnsigned(addUnsigned(I(b, c, d), x), ac));
return addUnsigned(rotateLeft(a, s), b);
};
var convertToWordArray = function(string) {
var lWordCount;
var lMessageLength = string.length;
var lNumberOfWordsTempOne = lMessageLength + 8;
var lNumberOfWordsTempTwo = (lNumberOfWordsTempOne - (lNumberOfWordsTempOne % 64)) / 64;
var lNumberOfWords = (lNumberOfWordsTempTwo + 1) * 16;
var lWordArray = Array(lNumberOfWords - 1);
var lBytePosition = 0;
var lByteCount = 0;
while(lByteCount < lMessageLength) {
lWordCount = (lByteCount - (lByteCount % 4)) / 4;
lBytePosition = (lByteCount % 4) * 8;
lWordArray[lWordCount] = (lWordArray[lWordCount] | (string.charCodeAt(lByteCount) << lBytePosition));
lByteCount++;
}
lWordCount = (lByteCount - (lByteCount % 4)) / 4;
lBytePosition = (lByteCount % 4) * 8;
lWordArray[lWordCount] = lWordArray[lWordCount] | (0x80 << lBytePosition);
lWordArray[lNumberOfWords - 2] = lMessageLength << 3;
lWordArray[lNumberOfWords - 1] = lMessageLength >>> 29;
return lWordArray;
};
var wordToHex = function(lValue) {
var WordToHexValue = "",
WordToHexValueTemp = "",
lByte, lCount;
for(lCount = 0; lCount <= 3; lCount++) {
lByte = (lValue >>> (lCount * 8)) & 255;
WordToHexValueTemp = "0" + lByte.toString(16);
WordToHexValue = WordToHexValue + WordToHexValueTemp.substr(WordToHexValueTemp.length - 2, 2);
}
return WordToHexValue;
};
var uTF8Encode = function(string) {
string = string.replace(/\x0d\x0a/g, "\x0a");
var output = "";
for(var n = 0; n < string.length; n++) {
var c = string.charCodeAt(n);
if(c < 128) {
output += String.fromCharCode(c);
} else if((c > 127) && (c < 2048)) {
output += String.fromCharCode((c >> 6) | 192);
output += String.fromCharCode((c & 63) | 128);
} else {
output += String.fromCharCode((c >> 12) | 224);
output += String.fromCharCode(((c >> 6) & 63) | 128);
output += String.fromCharCode((c & 63) | 128);
}
}
return output;
};
function md5(string) {
var x = Array();
var k, AA, BB, CC, DD, a, b, c, d;
var S11 = 7,
S12 = 12,
S13 = 17,
S14 = 22;
var S21 = 5,
S22 = 9,
S23 = 14,
S24 = 20;
var S31 = 4,
S32 = 11,
S33 = 16,
S34 = 23;
var S41 = 6,
S42 = 10,
S43 = 15,
S44 = 21;
string = uTF8Encode(string);
x = convertToWordArray(string);
a = 0x67452301;
b = 0xEFCDAB89;
c = 0x98BADCFE;
d = 0x10325476;
for(k = 0; k < x.length; k += 16) {
AA = a;
BB = b;
CC = c;
DD = d;
a = FF(a, b, c, d, x[k + 0], S11, 0xD76AA478);
d = FF(d, a, b, c, x[k + 1], S12, 0xE8C7B756);
c = FF(c, d, a, b, x[k + 2], S13, 0x242070DB);
b = FF(b, c, d, a, x[k + 3], S14, 0xC1BDCEEE);
a = FF(a, b, c, d, x[k + 4], S11, 0xF57C0FAF);
d = FF(d, a, b, c, x[k + 5], S12, 0x4787C62A);
c = FF(c, d, a, b, x[k + 6], S13, 0xA8304613);
b = FF(b, c, d, a, x[k + 7], S14, 0xFD469501);
a = FF(a, b, c, d, x[k + 8], S11, 0x698098D8);
d = FF(d, a, b, c, x[k + 9], S12, 0x8B44F7AF);
c = FF(c, d, a, b, x[k + 10], S13, 0xFFFF5BB1);
b = FF(b, c, d, a, x[k + 11], S14, 0x895CD7BE);
a = FF(a, b, c, d, x[k + 12], S11, 0x6B901122);
d = FF(d, a, b, c, x[k + 13], S12, 0xFD987193);
c = FF(c, d, a, b, x[k + 14], S13, 0xA679438E);
b = FF(b, c, d, a, x[k + 15], S14, 0x49B40821);
a = GG(a, b, c, d, x[k + 1], S21, 0xF61E2562);
d = GG(d, a, b, c, x[k + 6], S22, 0xC040B340);
c = GG(c, d, a, b, x[k + 11], S23, 0x265E5A51);
b = GG(b, c, d, a, x[k + 0], S24, 0xE9B6C7AA);
a = GG(a, b, c, d, x[k + 5], S21, 0xD62F105D);
d = GG(d, a, b, c, x[k + 10], S22, 0x2441453);
c = GG(c, d, a, b, x[k + 15], S23, 0xD8A1E681);
b = GG(b, c, d, a, x[k + 4], S24, 0xE7D3FBC8);
a = GG(a, b, c, d, x[k + 9], S21, 0x21E1CDE6);
d = GG(d, a, b, c, x[k + 14], S22, 0xC33707D6);
c = GG(c, d, a, b, x[k + 3], S23, 0xF4D50D87);
b = GG(b, c, d, a, x[k + 8], S24, 0x455A14ED);
a = GG(a, b, c, d, x[k + 13], S21, 0xA9E3E905);
d = GG(d, a, b, c, x[k + 2], S22, 0xFCEFA3F8);
c = GG(c, d, a, b, x[k + 7], S23, 0x676F02D9);
b = GG(b, c, d, a, x[k + 12], S24, 0x8D2A4C8A);
a = HH(a, b, c, d, x[k + 5], S31, 0xFFFA3942);
d = HH(d, a, b, c, x[k + 8], S32, 0x8771F681);
c = HH(c, d, a, b, x[k + 11], S33, 0x6D9D6122);
b = HH(b, c, d, a, x[k + 14], S34, 0xFDE5380C);
a = HH(a, b, c, d, x[k + 1], S31, 0xA4BEEA44);
d = HH(d, a, b, c, x[k + 4], S32, 0x4BDECFA9);
c = HH(c, d, a, b, x[k + 7], S33, 0xF6BB4B60);
b = HH(b, c, d, a, x[k + 10], S34, 0xBEBFBC70);
a = HH(a, b, c, d, x[k + 13], S31, 0x289B7EC6);
d = HH(d, a, b, c, x[k + 0], S32, 0xEAA127FA);
c = HH(c, d, a, b, x[k + 3], S33, 0xD4EF3085);
b = HH(b, c, d, a, x[k + 6], S34, 0x4881D05);
a = HH(a, b, c, d, x[k + 9], S31, 0xD9D4D039);
d = HH(d, a, b, c, x[k + 12], S32, 0xE6DB99E5);
c = HH(c, d, a, b, x[k + 15], S33, 0x1FA27CF8);
b = HH(b, c, d, a, x[k + 2], S34, 0xC4AC5665);
a = II(a, b, c, d, x[k + 0], S41, 0xF4292244);
d = II(d, a, b, c, x[k + 7], S42, 0x432AFF97);
c = II(c, d, a, b, x[k + 14], S43, 0xAB9423A7);
b = II(b, c, d, a, x[k + 5], S44, 0xFC93A039);
a = II(a, b, c, d, x[k + 12], S41, 0x655B59C3);
d = II(d, a, b, c, x[k + 3], S42, 0x8F0CCC92);
c = II(c, d, a, b, x[k + 10], S43, 0xFFEFF47D);
b = II(b, c, d, a, x[k + 1], S44, 0x85845DD1);
a = II(a, b, c, d, x[k + 8], S41, 0x6FA87E4F);
d = II(d, a, b, c, x[k + 15], S42, 0xFE2CE6E0);
c = II(c, d, a, b, x[k + 6], S43, 0xA3014314);
b = II(b, c, d, a, x[k + 13], S44, 0x4E0811A1);
a = II(a, b, c, d, x[k + 4], S41, 0xF7537E82);
d = II(d, a, b, c, x[k + 11], S42, 0xBD3AF235);
c = II(c, d, a, b, x[k + 2], S43, 0x2AD7D2BB);
b = II(b, c, d, a, x[k + 9], S44, 0xEB86D391);
a = addUnsigned(a, AA);
b = addUnsigned(b, BB);
c = addUnsigned(c, CC);
d = addUnsigned(d, DD);
}
var tempValue = wordToHex(a) + wordToHex(b) + wordToHex(c) + wordToHex(d);
return tempValue.toLowerCase();
}
module.exports.md5 = md5采坑：
1.签名所需key不是小程序的key值，而是商户号的秘钥(ps:秘钥不可再次查看，只能重置，所以小伙伴们要记住秘钥哦)
2.其中MD5签名，需要引用js文件到项目中，我放到项目的utils文件夹中
3.签名规则
◆ 参数名ASCII码从小到大排序（字典序）；
◆ 如果参数的值为空不参与签名；
◆ 参数名区分大小写；
◆ 验证调用返回或微信主动通知签名时，传送的sign参数不参与签名，将生成的签名与该sign值作校验。
◆ 微信接口可能增加字段，验证签名时必须支持增加的扩展字段
验证签名算法是否正确的工具：
https://pay.weixin.qq.com/wiki/doc/api/jsapi.php?chapter=20_1
4.需要生成两次签名
相关文档地址：
微信支付方法:https://developers.weixin.qq.com/miniprogram/dev/api/api-pay.html
统一下单方法：https://pay.weixin.qq.com/wiki/doc/api/wxa/wxa_api.php?chapter=9_1
微信支付开发官方文档：https://pay.weixin.qq.com/wiki/doc/api/wxa/wxa_api.php?chapter=4_3
微信小程序API:https://mp.weixin.qq.com/debug/wxadoc/dev/api/api-pay.html#wxrequestpaymentobject
微信小程序业务流程：https://pay.weixin.qq.com/wiki/doc/api/wxa/wxa_api.php?chapter=7_4&index=2
特别感谢：莫兰迪不会没有瓶子
参考文档：
https://blog.csdn.net/zhaoyazhi2129/article/details/53941396