java_currency_exchange_app herokuUrl: 转换API GET {herokuUrl} / currencyConversion / {amount} / {currency} 参数: 数量:数字, 货币:字符串样本输出(成功): { “费率”:{ “ CAD”:155.10017, “ HKD”:953.69330, “ ISK”:15766.37285, ... }, “ base”:“ USD”, “ date”:“ 2021-02-19” } 引发错误: 内部服务器错误输入无效 汇率历史记录API GET {herokuUrl} / rateHist