请教签名问题

Api说明文件：https://help.aliyun.com/document_detail/50558.html?spm=5176.doc28436.2.9.BAM4Xh#h1-u7B7Eu540Du751Fu6210u65B9u5F0F

其中这一段：

请教例子中的签名字符串（http method, canonicalizedQueryString,）是不是：POST&%2F&AccessKeyId%3DtestAKID%26Action%3DTextKeywordFilter%26Format%3DJSON%26RegionId%3Dcn-hangzhou%26SignatureMethod%3DHMAC-SHA1%26SignatureNonce%3D75c85963-66a4-4fdb-9fcf-a4ead3d92c8a%26SignatureVersion%3D1.0%26Text%3D%25E6%25B3%2595%25E8%25BD%25AE%25E5%258A%259F%26Timestamp%3D2017-01-05T14%253A32%253A11Z%26Version%3D2016-12-16

AccessKeyId=testAKID&

始终无法计算出正确的签名，谢谢