iOS适配HTTPS，创建一个自签名的SSL证书（x509）具体步骤

/**
 AFSecurityPolicy分三种验证模式：
 AFSSLPinningModeNone:只是验证证书是否在信任列表中
 AFSSLPinningModeCertificate：该模式会验证证书是否在信任列表中，然后再对比服务端证书和客户端证书是否一致
 AFSSLPinningModePublicKey：只验证服务端证书与客户端证书的公钥是否一致
*/
 
AFSecurityPolicy *securityPolicy = [AFSecurityPolicy policyWithPinningMode:AFSSLPinningModeCertificate];
    securityPolicy.allowInvalidCertificates = YES;//是否允许使用自签名证书
    securityPolicy.validatesDomainName = NO;//是否需要验证域名，默认YES
 
    AFHTTPSessionManager *_manager = [AFHTTPSessionManager manager];
    _manager.responseSerializer = [AFHTTPResponseSerializer serializer];
    _manager.securityPolicy = securityPolicy;
    //设置超时
    [_manager.requestSerializer willChangeValueForKey:@"timeoutinterval"];
    _manager.requestSerializer.timeoutInterval = 20.f;
    [_manager.requestSerializer didChangeValueForKey:@"timeoutinterval"];
    _manager.requestSerializer.cachePolicy = NSURLRequestReloadIgnoringCacheData;
    _manager.responseSerializer.acceptableContentTypes  = [NSSet setWithObjects:@"application/xml",@"text/xml",@"text/plain",@"application/json",nil];
  
    __weak typeof(self) weakSelf = self;
    [_manager setSessionDidReceiveAuthenticationChallengeBlock:^NSURLSessionAuthChallengeDisposition(NSURLSession *session, NSURLAuthenticationChallenge *challenge, NSURLCredential *__autoreleasing *_credential) {
         
        SecTrustRef serverTrust = [[challenge protectionSpace] serverTrust];
        /**
         *  导入多张CA证书
         */
        NSString *cerPath = [[NSBundle mainBundle] pathForResource:@"ca" ofType:@"cer"];//自签名证书
        NSData* caCert = [NSData dataWithContentsOfFile:cerPath];
        NSArray *cerArray = @[caCert];
        weakSelf.manager.securityPolicy.pinnedCertificates = cerArray;
         
        SecCertificateRef caRef = SecCertificateCreateWithData(NULL, (__bridge CFDataRef)caCert);
        NSCAssert(caRef != nil, @"caRef is nil");
         
        NSArray *caArray = @[(__bridge id)(caRef)];
        NSCAssert(caArray != nil, @"caArray is nil");
         
        OSStatus status = SecTrustSetAnchorCertificates(serverTrust, (__bridge CFArrayRef)caArray);
        SecTrustSetAnchorCertificatesOnly(serverTrust,NO);
        NSCAssert(errSecSuccess == status, @"SecTrustSetAnchorCertificates failed");
         
        NSURLSessionAuthChallengeDisposition disposition = NSURLSessionAuthChallengePerformDefaultHandling;
        __autoreleasing NSURLCredential *credential = nil;
        if ([challenge.protectionSpace.authenticationMethod isEqualToString:NSURLAuthenticationMethodServerTrust]) {
            if ([weakSelf.manager.securityPolicy evaluateServerTrust:challenge.protectionSpace.serverTrust forDomain:challenge.protectionSpace.host]) {
                credential = [NSURLCredential credentialForTrust:challenge.protectionSpace.serverTrust];
                if (credential) {
                    disposition = NSURLSessionAuthChallengeUseCredential;
                } else {
                    disposition = NSURLSessionAuthChallengePerformDefaultHandling;
                }
            } else {
                disposition = NSURLSessionAuthChallengeCancelAuthenticationChallenge;
            }
        } else {
            disposition = NSURLSessionAuthChallengePerformDefaultHandling;
        }
         
        return disposition;
    }];