MKWebFileDownloader

基于NSOperationQueue与NSURLSessionDataTask实现的文件下载器（支持设置队列并发数量、任务优先级、断点续传）

- (void)download {
    [MKWebFileDownloader sharedInstance].delegateOnMainThread = YES;
    [MKWebFileDownloader sharedInstance].maxConcurrentOperationCount = 6;

    NSString *URLString = @"https://dldir1.qq.com/qqfile/QQforMac/QQ_V6.5.0.dmg";
    [[MKWebFileDownloader sharedInstance] downloadWithURLString:URLString supportResume:YES directory:nil queuePriority:NSOperationQueuePriorityNormal progressHandler:^(NSInteger receivedSize, NSInteger expectedSize) {
        NSString *statusInfo = [NSString stringWithFormat:@"下载进度：%d%@", (int)(1.0*receivedSize/expectedSize * 100), @"%"];
        NSLog(@"%@", statusInfo);
    } completionHandler:^(NSString *filePath, NSData *fileData, NSError *error) {
        NSLog(@"下载完成");
    }];
}