1.简单的实现小文件的下载
NSURL *url = [NSURL URLWithString:@"文件下载地址"];
//2.创建请求对象
NSURLRequest *request = [NSURLRequest requestWithURL:url];
//3.发送请求
[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse * _Nullable response, NSData * _Nullable data, NSError * _Nullable connectionError) {
//4.写数据到沙盒中
NSString *fullPath = [[NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject]stringByAppendingPathComponent:@"123.mp4"];
[data writeToFile:fullPath atomically:YES];
}];
在iOS9.0以后使用NSURLSession类,之前用NSURLConnection来实现网络的请求,该种方法虽然可以下载小文件但是存在问题:
1.无法监听下载精度;
2.内存会随着文件的大小飙升
2.简单的实现小文件的下载(实现监听下载进度设置代理)
NSURL *url = [NSURL URLWithString:@"文件下载地址"];
//2.创建请求对象
NSURLRequest *request = [NSURLRequest requestWithURL:url];
//3.发送请求
[[NSURLConnection alloc]initWithRequest:request delegate:self];
通过代理方法实现下载进度的监听
-(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
//得到文件的总大小(本次请求的文件数据的总大小)
self.totalSize = response.expectedContentLength;
}
-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
[self.fileData appendData:data];
//进度=已经下载/文件的总大小
NSLog(@"%f",1.0 * self.fileData.length /self.totalSize);
}
-(void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
}
-(void)connectionDidFinishLoading:(NSURLConnection *)connection
{
//4.写数据到沙盒中
NSString *fullPath = [[NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject]stringByAppendingPathComponent:@"123.mp4"];
[self.fileData writeToFile:fullPath atomically:YES];
NSLog(@"%@",fullPath);
}
