钱方支付-扫码支付（微信，支付宝）-优快云博客

本文介绍了一种使用Java实现的钱方支付SDK的实战过程，包括参数设置、签名生成、请求发送及结果处理等步骤，特别指出金额参数的特殊处理方式。

官方文档

官方文档调用用的是python写的，作为一名Android开发，看的我一脸懵逼，记录下自己写的方法

实战

1.首先是参数，这里的支付金额(txamt)填的是1，实际支付是0.01，切记不能填0.01，会返回参数txamt错误

        Map<String, String> map = new HashMap<>();
        map.put("txamt", "1");
        map.put("txcurrcd", "CNY");
        map.put("pay_type", type);
        map.put("out_trade_no", String.valueOf(System.currentTimeMillis()));
        map.put("txdtm", format);
        map.put("goods_name", "张雷");
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2.根据参数生成未签名的字符串，必须给Map的key和value进行编码转换,然后根据key升序排序,并后用&符号连接每个key和value（举个例子：a=b&c=d),最后拼接上钱方提供的key后MD5一下就完成了

    private String make_req_sign(Map<String, String> params, String key) {
        Set<String> keys = params.keySet();
        List<String> result = new ArrayList<>(keys);
        Collections.sort(result);
        StringBuilder data = new StringBuilder();
        for (String s : result) {
            Log.e("test", "make_req_sign: " + s);
            String k = unicodeToUtf8(s);
            String v = unicodeToUtf8(params.get(k));
            String format = String.format("%s=%s", k, v);
            data.append(format);
            data.append("&");
        }
        String unsign_str = "";
        if (data.length() > 0) {
            unsign_str = data.substring(0, data.length() - 1) + key;
        }
        Log.e("test", "make_req_sign:unsign_str = " + unsign_str);
        return MD5(unsign_str);
    }
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unicodeToUtf8方法

    /**
     * unicode 转换成 utf-8
     *
     * @param theString
     * @return
     * @author fanhui
     * 2007-3-15
     */
    public String unicodeToUtf8(String theString) {
        char aChar;
        int len = theString.length();
        StringBuffer outBuffer = new StringBuffer(len);
        for (int x = 0; x < len; ) {
            aChar = theString.charAt(x++);
            if (aChar == '\\') {
                aChar = theString.charAt(x++);
                if (aChar == 'u') {
                    // Read the xxxx
                    int value = 0;
                    for (int i = 0; i < 4; i++) {
                        aChar = theString.charAt(x++);
                        switch (aChar) {
                            case '0':
                            case '1':
                            case '2':
                            case '3':
                            case '4':
                            case '5':
                            case '6':
                            case '7':
                            case '8':
                            case '9':
                                value = (value << 4) + aChar - '0';
                                break;
                            case 'a':
                            case 'b':
                            case 'c':
                            case 'd':
                            case 'e':
                            case 'f':
                                value = (value << 4) + 10 + aChar - 'a';
                                break;
                            case 'A':
                            case 'B':
                            case 'C':
                            case 'D':
                            case 'E':
                            case 'F':
                                value = (value << 4) + 10 + aChar - 'A';
                                break;
                            default:
                                throw new IllegalArgumentException(
                                        "Malformed   \\uxxxx   encoding.");
                        }
                    }
                    outBuffer.append((char) value);
                } else {
                    if (aChar == 't')
                        aChar = '\t';
                    else if (aChar == 'r')
                        aChar = '\r';
                    else if (aChar == 'n')
                        aChar = '\n';
                    else if (aChar == 'f')
                        aChar = '\f';
                    outBuffer.append(aChar);
                }
            } else
                outBuffer.append(aChar);
        }
        return outBuffer.toString();
    }
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MD5方法

    private String MD5(String s) {
        try {
            MessageDigest md = MessageDigest.getInstance("MD5");
            byte[] bytes = md.digest(s.getBytes("utf-8"));
            return toHex(bytes);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    private String toHex(byte[] bytes) {

        final char[] HEX_DIGITS = "0123456789ABCDEF".toCharArray();
        StringBuilder ret = new StringBuilder(bytes.length * 2);
        for (int i = 0; i < bytes.length; i++) {
            ret.append(HEX_DIGITS[(bytes[i] >> 4) & 0x0f]);
            ret.append(HEX_DIGITS[bytes[i] & 0x0f]);
        }
        return ret.toString();
    }

}
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3.请求钱方接口获取签名信息,每个人的网络框架不同，我就贴一下关键代码（我用的是OkHttp）

                .addHeader("X-QF-APPCODE", "钱方的code")
                .addHeader("X-QF-SIGN", make_req_sign(map, "钱方的key"))
                .params(map)
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4.返回结果

{
    "pay_type": "800201",
    "sysdtm": "2016-04-11 17:58:34",
    "txdtm": "2016-04-11 17:51:00",
    "resperr": "",
    "txcurrcd": "CNY",
    "txamt": "1",
    "respmsg": "",
    "out_trade_no": "145399626053599943",
    "syssn": "20160411016600020003620875",
    "qrcode": "https://o2.qfpay.com/q/mid?h=zxrLRO8kbLV3QmqdgTm8da",
    "respcd": "0000"
}  
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