java调用百度云cdn刷新缓存接口问题，生成认证字符串不正确。

[杨对对_java]

我现在调用百度云cdn的刷新缓存接口，写的好烂，一直掉不通，demo都没有，认证字符串怎么生成太麻烦 ，一直调试不通，报这样错误：{"code":"SignatureDoesNotMatch","message":"The request signature we calculated does not match the signature you provided. Check your Secret Access Key and signing method. Consult the service documentation for details.","requestId":"017d7e82-2b6c-403b-8af1-1acb736958c9"}。急急急！这个是百度云的文档：https://cloud.baidu.com/doc/CDN/API.html#.E5.88.B7.E6.96.B0.E7.BC.93.E5.AD.98