错误描述：CFNetwork SSLHandshake failed (-9807)
A connection failure occurred: SSL problem (Possible causes may include a bad/expired/self-signed certificate, clock set to wrong date)
出现问题： 常见于HTTPS的证书，不合法。
解决方法，加入如下2行代码：
[objc]
[request setAuthenticationScheme:@"https"];//设置验证方式
[request setValidatesSecureCertificate:NO];//设置验证证书
[/objc]