AFNetworking 2.x 设置header

AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];manager.securityPolicy = [AFSecurityPolicy policyWithPinningMode:AFSSLPinningModeNone];manager.requestSerializer = [AFJSONRequestSerializer serializer];manager.responseSerializer = [AFJSONResponseSerializer serializer];[manager.requestSerializer setValue:@"application/json" forHTTPHeaderField:@"Accept"];[manager.requestSerializer setValue:@"application/json; charset=utf-8" forHTTPHeaderField:@"Content-Type"];