大文件下载

 1 @interface ViewController () {
 2     // 文件的总长度
 3     int _totalLength;
 4 }
 5 @property (nonatomic, retain) NSMutableData *data;
 6 @end
 7 
 8 @implementation ViewController
 9 - (void)dealloc {
10     [_data release];
11     [super dealloc];
12 }
13 
14 - (void)viewDidUnload {
15     [super viewDidUnload];
16     self.data = nil;
17 }
18 
19 - (void)viewDidLoad
20 {
21     [super viewDidLoad];
22     // Do any additional setup after loading the view, typically from a nib.
23     
24     
25 }
26 
27 - (void)download {
28     
29     self.data = [NSMutableData data];
30     
31     NSURL *url = [NSURL URLWithString:@"http://192.168.1.106:8080/Server/movie.avi"];
32     
33     NSURLRequest *reuqest = [NSURLRequest requestWithURL:url];
34     
35     [[NSURLConnection connectionWithRequest:reuqest delegate:self] start];
36 }
37 
38 #pragma mark - 代理方法
39 - (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
40     [self.data appendData:data];
41     
42     // 设置下载进度
43     self.progressView.progress = (float)self.data.length / (float)_totalLength;
44 }
45 
46 #pragma mark 服务器有相应就会调用这个方法
47 - (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
48     NSHTTPURLResponse *rep = (NSHTTPURLResponse *)response;
49     
50     _totalLength = [[[rep allHeaderFields] objectForKey:@"Content-Length"] intValue];
51 }
52 
53 - (void)connectionDidFinishLoading:(NSURLConnection *)connection {
54     NSString *cacheDir = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject];
55     
56     NSString *dir = [cacheDir stringByAppendingPathComponent:@"movie"];
57     
58     NSFileManager *mgr = [NSFileManager defaultManager];
59     
60     // 是否为文件夹
61     BOOL isDir;
62     // 是否存在
63     BOOL exist = [mgr fileExistsAtPath:dir isDirectory:&isDir];
64     if (!exist) {
65         // 创建一个新的文件夹
66         [mgr createDirectoryAtPath:dir withIntermediateDirectories:YES attributes:nil error:nil];
67     }
68     
69     NSString *path = [dir stringByAppendingPathComponent:@"mj.avi"];
70     // 将文件数据写入Library/Caches文件夹下
71     [self.data writeToFile:path atomically:YES];
72 }
73 @end