iOS 文件下载

1、小文件下载

@interface ViewController () <NSURLConnectionDataDelegate>@property (weak, nonatomic) IBOutlet UIProgressView *progressView;/** 文件数据 */@property (nonatomic, strong) NSMutableData *fileData;/** 文件的总长度 */@property (nonatomic, assign) NSInteger contentLength;@end

- (void)viewDidLoad {    [super viewDidLoad];    NSURL *url = [NSURL URLWithString:@"http://120.25.226.186:32812/resources/videos/minion_15.mp4"];    [NSURLConnection connectionWithRequest:[NSURLRequest requestWithURL:url] delegate:self];}#pragma mark - <NSURLConnectionDataDelegate>- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSHTTPURLResponse *)response{    self.contentLength = [response.allHeaderFields[@"Content-Length"] integerValue];    self.fileData = [NSMutableData data];}- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data{    [self.fileData appendData:data];    CGFloat progress = 1.0 * self.fileData.length / self.contentLength;    NSLog(@"已下载：%.2f%%", (progress) * 100);    self.progressView.progress = progress;}- (void)connectionDidFinishLoading:(NSURLConnection *)connection{    NSLog(@"下载完毕");        // 将文件写入沙盒中        // 缓存文件夹    NSString *caches = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject];        // 文件路径    NSString *file = [caches stringByAppendingPathComponent:@"minion_15.mp4"];        // 写入数据    [self.fileData writeToFile:file atomically:YES];    self.fileData = nil;}

2、大文件下载

#define XMGFile [[NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:@"minion_15.mp4"]@interface ViewController () <NSURLConnectionDataDelegate>@property (weak, nonatomic) IBOutlet UIProgressView *progressView;/** 文件的总长度 */@property (nonatomic, assign) NSInteger contentLength;/** 当前下载的总长度 */@property (nonatomic, assign) NSInteger currentLength;/** 文件句柄对象 */@property (nonatomic, strong) NSFileHandle *handle;@end

- (void)viewDidLoad {    [super viewDidLoad];        NSURL *url = [NSURL URLWithString:@"http://120.25.226.186:32812/resources/videos/minion_15.mp4"];    [NSURLConnection connectionWithRequest:[NSURLRequest requestWithURL:url] delegate:self];}

#pragma mark - <NSURLConnectionDataDelegate>/** * 接收到响应的时候：创建一个空的文件 */- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSHTTPURLResponse *)response{    // 获得文件的总长度    self.contentLength = [response.allHeaderFields[@"Content-Length"] integerValue];        // 创建一个空的文件    [[NSFileManager defaultManager] createFileAtPath:XMGFile contents:nil attributes:nil];        // 创建文件句柄    self.handle = [NSFileHandle fileHandleForWritingAtPath:XMGFile];}/** * 接收到具体数据：马上把数据写入一开始创建好的文件 */- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data{        // 指定数据的写入位置 -- 文件内容的最后面    [self.handle seekToEndOfFile];        // 写入数据    [self.handle writeData:data];        // 拼接总长度    self.currentLength += data.length;        // 进度    self.progressView.progress = 1.0 * self.currentLength / self.contentLength;}- (void)connectionDidFinishLoading:(NSURLConnection *)connection{    // 关闭handle    [self.handle closeFile];    self.handle = nil;        // 清空长度    self.currentLength = 0;}

大文件断点下载

// resumeData的文件路径#define XMGResumeDataFile [[NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:@"resumeData.tmp"]#import "ViewController.h"@interface ViewController () <NSURLSessionDownloadDelegate>/** 下载任务 */@property (nonatomic, strong) NSURLSessionDownloadTask *task;/** 保存上次的下载信息 */@property (nonatomic, strong) NSData *resumeData;/** session */@property (nonatomic, strong) NSURLSession *session;@end

@implementation ViewController/** session */- (NSURLSession *)session{    if (!_session) {        _session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration] delegate:self delegateQueue:[[NSOperationQueue alloc] init]];    }    return _session;}/** * 开始下载 */- (IBAction)start:(id)sender {        self.task = [self.session downloadTaskWithURL:[NSURL URLWithString:@"http://120.25.226.186:32812/resources/videos/minion_01.mp4"]];    [self.task resume];}/** * 暂停下载 */- (IBAction)pause:(id)sender {    // 一旦这个task被取消了，就无法再恢复    [self.task cancelByProducingResumeData:^(NSData *resumeData) {        self.resumeData = resumeData;    }];}/** * 继续下载 */- (IBAction)goOn:(id)sender {    self.task = [self.session downloadTaskWithResumeData:self.resumeData];    [self.task resume];}#pragma mark - <NSURLSessionDownloadDelegate>- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error{    NSLog(@"didCompleteWithError");        // 保存恢复数据    self.resumeData = error.userInfo[NSURLSessionDownloadTaskResumeData];}- (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didResumeAtOffset:(int64_t)fileOffset expectedTotalBytes:(int64_t)expectedTotalBytes{    NSLog(@"didResumeAtOffset");}/** * 每当写入数据到临时文件时，就会调用一次这个方法 * totalBytesExpectedToWrite:总大小 * totalBytesWritten: 已经写入的大小 * bytesWritten: 这次写入多少 */- (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didWriteData:(int64_t)bytesWritten totalBytesWritten:(int64_t)totalBytesWritten totalBytesExpectedToWrite:(int64_t)totalBytesExpectedToWrite{    NSLog(@"--------%f", 1.0 * totalBytesWritten / totalBytesExpectedToWrite);}/** *  * 下载完毕就会调用一次这个方法 */- (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didFinishDownloadingToURL:(NSURL *)location{    // 文件将来存放的真实路径    NSString *file = [[NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:downloadTask.response.suggestedFilename];        // 剪切location的临时文件到真实路径    NSFileManager *mgr = [NSFileManager defaultManager];    [mgr moveItemAtURL:location toURL:[NSURL fileURLWithPath:file] error:nil];}@end