1.2数据签名

联盟成员注册后才能使用，注册成功后，每个联盟成员有一个身份ID和一个KEY，调用接口时必须传入身份ID(参数名为：union_id)和用数据签名。
JSON排序：当生成签名时，data对象中的键值对必须按照字典顺序（即字母顺序）进行排序。这是因为不同的排序会导致不同的字符串表示，从而导致不同的MD5哈希值。
sign生成方法：对请求中的data数据加上**key=分配给成员的KEY**，进行MD5并转为大写。

示例：上传车场信息
原始请求为：
{"data":{"park_id":"1001","name":"北京上地三街9号院停车场","address":"北京上地三街9号","phone":"139000334443","lng":"123.994449","city_id":110000,"lat":"332.466666","total_plot":90,"empty_plot":56,"union_id":10001,"price_desc":"2元每小时","rand":"0.210354312785198048"}}

签名方法：
data后面加上：key=NQ0eSXs720170114 得到（NQ0eSXs720170114为分配给联盟成员的KEY）：{"park_id":"1001","name":"北京上地三街9号院停车场","address":"北京上地三街9号","phone":"139000334443","lng":"123.994449","city_id":110000,"lat":"332.466666","total_plot":90,"empty_plot":56,"union_id":10001,"price_desc":"2元每小时","rand":"0.210354312785198048"}key=NQ0eSXs720170114
对上面的字符串MD5并大写得到：F2BA9A4E4362E2C41676FC720B14290C，在MD5方法中，取字节时使用**utf-8码**

请求数据为：
{"data":{"park_id":"1001","name":"北京上地三街9号院停车场","address":"北京上地三街9号","phone":"139000334443","lng":"123.994449","city_id":110000,"lat":"332.466666","total_plot":90,"empty_plot":56,"union_id":10001,"price_desc":"2元每小时","rand":"0.210354312785198048"},"sign":"F2BA9A4E4362E2C41676FC720B14290C"}

返回结果：
{"park_id":"1001","state":1}