【iOS开发-网络】大文件的断点续传(断点下载)

//暂停
if(sender.selected) {

[self.conn cancel];//取消连接
self.conn = nil;

//开始
} else {

//创建url
NSURL *url = [NSURL URLWithString:@"http://localhost:8080/TFServer/resources/videos/minion_01.mp4"];

//创建请求 这里不是NSURLRequest
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];

//创建头信息
NSString *range = [NSString stringWithFormat:@"bytes=%lld-", self.fileLength];

//设置头信息
[request setValue:range forHTTPHeaderField:@"Range"];

//发出一个异步请求
self.conn = [NSURLConnection connectionWithRequest:request delegate:self];
}