系统对接API调用

在与公司外部系统对接时，API接口一般采用REST风格，对外暴露HTTP服务。只需要将入参封装好，并发起HTTP请求即可。具体请求流程如下图所示：

数据格式

API调用参数分为系统参数和业务参数，请求时，系统参数是必传的，否则无法成功请求，业务参数由具体业务接口定义。

系统参数
名称	类型	必填	描述
apiKey	String	是	分配给供应商的唯一身份标识
sign	String	是	请求签名，生成规则参见签名机制
timestamp	String	是	时间戳，参见时间戳

API请求返回结果目前支持json和xml格式，具体返回格式由请求头中的Content-Type属性来决定。当Content-Type属性为application/xml时，返回xml格式，其余情况下统一返回json格式。返回结果包含以下字段

系统参数
名称	类型	必填	描述
returnCode	int	是	结果码，具体值参见API返回码
errorMsg	String	否	异常时错误信息
data	String	否	返回结果
success	boolean	是	是否请求成功

请求示例

我们以团期信息管理接口为例，假设我们需要维护团期，接口请求原始入参（业务参数+系统参数）如下.

{
    "apiKey": "testApiKey",//系统参数
    "timestamp": "2015-07-30 12:34:56",//系统参数
    "agencyProductId": "test10001",//业务参数
    "groupNum": "",//业务参数
    "planInfo": [//业务参数
        {
            "planDateStr": "2015-07-18",
            "datePriceList": [
                {
                    "schemeId": "scheme0001",
                    "scheduleId": "schedule",
                    "agencyBudget": 1000,
                    "agencyBudgetChild": 500,
                    "excludeChild": 1,
                    "roomAddBudget": 100,
                    "roomGapFlag": 1,
                    "aheaddate": 4,
                    "deadlinedate": 3,
                    "deadlinehour": 18,
                    "promoFlag": 1,
                    "setGroupFlag": 1,
                    "stuffEndDate": 5
                }
            ]
        }
    ]
}

首先，我们需要根据现有参数生成签名，签名生成步骤如下：

1. 将入参按照一级key值进行排序（按字典顺序进行排序，忽略大小写），去掉value值为空的入参，我们将得到以下格式参数(业务参数+系统参数）如下

{
    "agencyProductId": "test10001",
    "apiKey": "testApiKey",
    "planInfo": [
        {
            "planDateStr": "2015-07-18",
            "datePriceList": [
                {
                    "schemeId": "scheme0001",
                    "scheduleId": "schedule",
                    "agencyBudget": 1000,
                    "agencyBudgetChild": 500,
                    "excludeChild": 1,
                    "roomAddBudget": 100,
                    "roomGapFlag": 1,
                    "aheaddate": 4,
                    "deadlinedate": 3,
                    "deadlinehour": 18,
                    "promoFlag": 1,
                    "setGroupFlag": 1,
                    "stuffEndDate": 5
                }
            ]
        }
    ],
    "timestamp": "2015-07-30 12:34:56"
}

2. 获取一级key和对应的value，例如上面参数中planInfo键，对应的值为[{"planDateStr":"2015-07-18","datePriceList":[{"schemeId":"scheme0001","scheduleId":"schedule","agencyBudget":1000,"agencyBudgetChild":500,"excludeChild":1,"roomAddBudget":100,"roomGapFlag":1,"aheaddate":4,"deadlinedate":3,"deadlinehour":18,"promoFlag":1,"setGroupFlag":1,"stuffEndDate":5}]}]， 以字符串的形式把key+value拼接起来得到一个新的字符串（二级三级键不进行操作），如下：

planInfo[{"planDateStr":"2015-07-18","datePriceList":[{"schemeId":"scheme0001","scheduleId":"schedule","agencyBudget":1000,
"agencyBudgetChild":500,"excludeChild":1,"roomAddBudget":100,"roomGapFlag":1,"aheaddate":4,"deadlinedate":3,"deadlinehour":18,
"promoFlag":1,"setGroupFlag":1,"stuffEndDate":5}]}]

其他键值对同样如此，将拼装好的字符串再依次拼接起来，如下：

agencyProductIdtest10001apiKeytestApiKeyplanInfo[{"planDateStr":"2015-07-18","datePriceList":[{"schemeId":"scheme0001","scheduleId":"schedule",
"agencyBudget":1000,"agencyBudgetChild":500,"excludeChild":1,"roomAddBudget":100,"roomGapFlag":1,"aheaddate":4,"deadlinedate":3,"deadlinehour":18,
"promoFlag":1,"setGroupFlag":1,"stuffEndDate":5}]}]timestamp2015-07-30 12:34:56

3. 在拼好的字符串前后都加上签名密钥，我们假设密钥是ZbWjUMYevqT9Tnup4jRs,可以得到以下字符串：

ZbWjUMYevqT9Tnup4jRsagencyProductIdtest10001apiKeytestApiKeyplanInfo[{"planDateStr":"2015-07-18","datePriceList":[{"schemeId":"scheme0001",
"scheduleId":"schedule","agencyBudget":1000,"agencyBudgetChild":500,"excludeChild":1,"roomAddBudget":100,"roomGapFlag":1,"aheaddate":4,
"deadlinedate":3,"deadlinehour":18,"promoFlag":1,"setGroupFlag":1,"stuffEndDate":5}]}]timestamp2015-07-30 12:34:56ZbWjUMYevqT9Tnup4jRs

4. 对生成的字符串进行MD5加密，并将结果全部转为大写，获得签名值:

85F60EFE28BB4688F3BA4A37FF62C101

5. 将签名加入到入参中：

{
    "agencyProductId": "test10001",
    "apiKey": "testApiKey",
    "planInfo": [
        {
            "planDateStr": "2015-07-18",
            "datePriceList": [
                {
                    "schemeId": "scheme0001",
                    "scheduleId": "schedule",
                    "agencyBudget": 1000,
                    "agencyBudgetChild": 500,
                    "excludeChild": 1,
                    "roomAddBudget": 100,
                    "roomGapFlag": 1,
                    "aheaddate": 4,
                    "deadlinedate": 3,
                    "deadlinehour": 18,
                    "promoFlag": 1,
                    "setGroupFlag": 1,
                    "stuffEndDate": 5
                }
            ]
        }
    ],
    "timestamp": "2015-07-30 12:34:56",
    "sign": "85F60EFE28BB4688F3BA4A37FF62C101"
}

6.发起HTTP请求。

附上MD5加密方法参考示例：

private static String Md5Encode(String str) throws NoSuchAlgorithmException {
    StringBuilder sign = new StringBuilder();

    MessageDigest md = MessageDigest.getInstance("MD5");
    byte[] bytes = md.digest(str.getBytes());

    for (int i = 0; i < bytes.length; i++) {
        String hex = Integer.toHexString(bytes[i] & 0xFF);
        if (hex.length() == 1) {
            sign.append("0");
        }
        sign.append(hex.toUpperCase());
    }
    return sign.toString();
}

在spring-core包中提供了一个MD5加密工具！

org.springframework.util.DigestUtils#md5DigestAsHex(byte[])

注意事项

1. 所有的请求和响应数据编码皆为utf-8格式

2. 生成签名时，空值的参数不参与校验

3. 生成签名时，参数名称和值大小写敏感

4. 排序规则为按字典顺序进行排序，忽略大小写

附代码实现：

public class APITest {
    public static void main(String[] args) throws NoSuchAlgorithmException {
        String s = "{\n" +
                "    \"apiKey\": \"testApiKey\",\n" +
                "    \"timestamp\": \"2015-07-30 12:34:56\",\n" +
                "    \"agencyProductId\": \"test10001\",\n" +
                "    \"groupNum\": \"\",\n" +
                "    \"planInfo\": [\n" +
                "        {\n" +
                "            \"planDateStr\": \"2015-07-18\",\n" +
                "            \"datePriceList\": [\n" +
                "                {\n" +
                "                    \"schemeId\": \"scheme0001\",\n" +
                "                    \"scheduleId\": \"schedule\",\n" +
                "                    \"agencyBudget\": 1000,\n" +
                "                    \"agencyBudgetChild\": 500,\n" +
                "                    \"excludeChild\": 1,\n" +
                "                    \"roomAddBudget\": 100,\n" +
                "                    \"roomGapFlag\": 1,\n" +
                "                    \"aheaddate\": 4,\n" +
                "                    \"deadlinedate\": 3,\n" +
                "                    \"deadlinehour\": 18,\n" +
                "                    \"promoFlag\": 1,\n" +
                "                    \"setGroupFlag\": 1,\n" +
                "                    \"stuffEndDate\": 5\n" +
                "                }\n" +
                "            ]\n" +
                "        }\n" +
                "    ]\n" +
                "}";
        String signature = getSignature(s, "ZbWjUMYevqT9Tnup4jRs");
        System.out.println(Md5Encode(signature));
    }

    public static String getSignature(String requestData, String secretKey) {
        //第一步,获取所有值非空的key
        List<String> keyList = new ArrayList<String>();
        Map<String,Object> data = JsonUtil.toBean(requestData,Map.class);
        for (String key : data.keySet()) {
            if (key == null) {
                continue;
            }
            //value为null或空
            if (data.get(key) == null || StringUtils.isBlank(data.get(key).toString())) {
                continue;
            }
            keyList.add(key);
        }
        //按名称排序并拼接成字符串
        String[] arrayToSort = keyList.toArray(new String[keyList.size()]);
        Arrays.sort(arrayToSort, String.CASE_INSENSITIVE_ORDER);
        StringBuilder sb = new StringBuilder(secretKey);
        for (String key : arrayToSort) {
            sb.append(key);
            sb.append(JsonUtil.toString(data.get(key)));
        }
        sb.append(secretKey);
        System.out.println(sb.toString());
        return sb.toString();
    }

    /**
     * MD5 加密
     * @param str 需要加密的字符串
     * @return 经过加密的字符串
     * @throws NoSuchAlgorithmException
     */
    private static String Md5Encode(String str) throws NoSuchAlgorithmException {
        StringBuilder sign = new StringBuilder();
        MessageDigest md = MessageDigest.getInstance("MD5");
        byte[] bytes = md.digest(str.getBytes());

        for (int i = 0; i < bytes.length; i++) {
            String hex = Integer.toHexString(bytes[i] & 0xFF);
            if (hex.length() == 1) {
                sign.append("0");
            }
            sign.append(hex.toUpperCase());
        }
        return sign.toString();
    }
}