這種情況通常是因為在調用的時候，package參數有問題導致；
最可能的原因是：你在測試的權限不夠不是開發者權限，獲取小程序的oppid失敗，缺少oppid所以獲取不到prepay_id=''的值
wx.requestPayment中package參數必須是package:"prepay_id=wx21**************"，不然，會出現調用支付JSAPI缺少appid/total_fee；
正常情況下：
//{"appid":"wx0411fa6a39d61297","noncestr":"3reA4pSqGBPPryEL","package":"Sign=WXPay","partnerid":"1230636401","prepayid":"wx20170406175858b261288c050041764688","timestamp":1491472738,"sign":"4A50B67D47E062A1F3B739D76C683D37"}
//{"appid":"wx05a63e391546d945","noncestr":"Uvxaj0yZeE5uw0Wd","package":"Sign=WXPay","partnerid":"1460680002","prepayid":"wx201704221807041af49e25c90779187614","timestamp":1492855550,"sign":"08FB66188544D438DF074F815EB585DF"}
如下出現問題：
