1、创建一个NSURLConnection对象:
NSURL *url = [NSURL URLWithString: @"http://119.147.106.249/gdown_group11/M00/3F/15/d5Nq-UxBq88AAAAAAUn8QBO4rlY4306605/01_01_Android%E5%B9%B3%E5%8F%B0%E4%B8%80%E6%97%A5%E6%B8%B8.mp4?k=-4hoIXm9CXQ_Zo79EQprcQ&t=1346820047&u=3662410469-66934941-bei9apjt&s=307200&file=01_01_Android%E5%B9%B3%E5%8F%B0%E4%B8%80%E6%97%A5%E6%B8%B8.mp4"];
NSURLRequest *request = [[NSURLRequest alloc] initWithURL:url cachePolicy:NSURLRequestReloadIgnoringCacheData timeoutInterval: 100.0];//设置缓存和超时
NSURLConnection *connection = nil;
connection = [[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:YES];
//初始化connection对象并马上执行,有的初始化方法并不是马上开始执行,而需要调用start方法。
二、实现connection的回调方法:
- (void)connection NSURLConnection *)connection didReceiveResponse NSURLResponse *)response
{//该方法在响应connection时调用
NSLog(@"response");
self.data = [[NSMutableData alloc] init];
NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)response;
if(httpResponse && [httpResponse respondsToSelector:@selector(allHeaderFields)]){
NSDictionary *httpResponseHeaderFields = [httpResponse allHeaderFields];
mFileSize = [[httpResponseHeaderFields objectForKey:@"Content-Length"] longLongValue];
}//获取文件文件的大小
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{//出错时调用
NSLog(@"error");
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{//接受数据,在接受完成之前,该方法重复调用
NSLog(@"receive");
[_data appendData: data];
_displayLabel.text = [NSString stringWithFormat:(@"%6.1fkb/%6.1fkb"),[_data length]/1024.0,mFileSize/1024.0];
[_progressView setProgress: [_data length]/(float)mFileSize];
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{//完成时调用
NSLog(@"Finish");
NSString *filePath = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0] stringByAppendingPathComponent:@"android.mp4"];
[_data writeToFile:filePath atomically:NO];//将数据写入Documents目录。
NSLog(@"%@",filePath);
}