cache
1、afnetworking默认的NSURLSessionConfiguration

    NSURLSessionConfiguration *configuration = [NSURLSessionConfiguration defaultSessionConfiguration];

    //TODO set the default HTTP headers

    configuration.HTTPShouldSetCookies = YES;
    configuration.HTTPShouldUsePipelining = NO;

    configuration.requestCachePolicy = NSURLRequestUseProtocolCachePolicy;
    configuration.allowsCellularAccess = YES;
    configuration.timeoutIntervalForRequest = 60.0;
    configuration.URLCache = [AFImageDownloader defaultURLCache]; // NSURLCache
    return configuration;



+ (NSURLCache *)defaultURLCache {
    return [[NSURLCache alloc] initWithMemoryCapacity:20 * 1024 * 1024
                                         diskCapacity:150 * 1024 * 1024
                                             diskPath:@"com.alamofire.imagedownloader"];
}

2、系统默认的NSURLSessionConfiguration

    if (!configuration) {
        configuration = [NSURLSessionConfiguration defaultSessionConfiguration];
    }


[NSURLSession sessionWithConfiguration:self.sessionConfiguration delegate:self delegateQueue:self.operationQueue]

3、UIWebView
UIWebView+AFNetworking// 替换UIWebView加载网页的默认的方法- (void)loadRequest:(NSURLRequest *)request;

用NSURLSession下载数据，然后用UIWebview下面的方法加载URLSession加载成的数据

- (void)loadData:(NSData *)data MIMEType:(NSString *)MIMEType textEncodingName:(NSString *)textEncodingName baseURL:(NSURL *)baseURL; 




    NSURLSessionDataTask *dataTask;
    dataTask = [self.sessionManager
            GET:request.URL.absoluteString
            parameters:nil
            progress:nil
            success:^(NSURLSessionDataTask * _Nonnull task, id  _Nonnull responseObject) {
                __strong __typeof(weakSelf) strongSelf = weakSelf;
                if (success) {
                    success((NSHTTPURLResponse *)task.response, responseObject);
                }
                [strongSelf loadData:responseObject MIMEType:MIMEType textEncodingName:textEncodingName baseURL:[task.currentRequest URL]];

                if ([strongSelf.delegate respondsToSelector:@selector(webViewDidStartLoad:)]) {
                    [strongSelf.delegate webViewDidFinishLoad:strongSelf];
                }
            }
            failure:^(NSURLSessionDataTask * _Nonnull task, NSError * _Nonnull error) {
                if (failure) {
                    failure(error);
                }
            }];
    self.af_URLSessionTask = dataTask;