简单实现断点下载

忘是亡心i 2022-09-23 14:48 208阅读 0赞

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@interface ViewController ()<NSURLSessionDelegate>

@property (weak,  nonatomic) IBOutletUIProgressView \*progressView;

@property (weak,  nonatomic) IBOutletUIButton \*startBtn;

@property (weak,  nonatomic) IBOutletUIButton \*stopBtn;

@property (weak,  nonatomic) IBOutletUIProgressView \*secondPV;

@property (nonatomic, strong) NSMutableDictionary \*tasks;

@property (nonatomic, strong) NSOutputStream \*stream; // 流

@property (nonatomic,assign) NSInteger fileTotalLength; // 文件总长度

@property (nonatomic,strong) NSMutableArray \*urlArray; // 需要下载的URL

@property (nonatomic,strong) NSURLSession \*session;

@property (nonatomic,assign) int index; // 任务标识

@property (nonatomic,strong) NSMutableArray \*filePathArray; // 本地file记录

@end

@implementation ViewController

\- (void)viewDidLoad \{

\[superviewDidLoad\];

\_session = \[NSURLSessionsessionWithConfiguration:\[NSURLSessionConfigurationdefaultSessionConfiguration\] delegate:selfdelegateQueue:\[\[NSOperationQueuealloc\] init\]\];

\_urlArray = \[\[NSMutableArrayalloc\]init\];

\[\_urlArrayaddObject:@"http://120.25.226.186:32812/resources/videos/minion\_01.mp4"\];

\[\_urlArrayaddObject:@"http://pic6.nipic.com/20100330/4592428\_113348097000\_2.jpg"\];

\_filePathArray = \[\[NSMutableArrayalloc\]init\];

//  任务队列处理

\[self taskQueue:\_urlArray\];

// 队列处理任务

\- (void)taskQueue:(NSMutableArray \*)urlArray\{

for (NSString \*requestUrl in urlArray) \{

NSString \*filePath = \[self fileCheck:requestUrl\];

\[\_filePathArray  addObject:filePath\];

NSMutableURLRequest \*request = \[NSMutableURLRequestrequestWithURL:\[NSURLURLWithString:requestUrl\]\];

\[self requestHead:request path:filePath\];

//  创建一个Data任务

NSURLSessionDataTask \*task = \[\_session dataTaskWithRequest:request\];

// 保存任务

\[self.tasks setValue:task forKey:requestUrl\];

/\*\*

\*  根据url获得对应的下载任务

\*/

\- (NSURLSessionDataTask \*)getTask:(NSString \*)url

return (NSURLSessionDataTask \*)\[self.tasksvalueForKey:url\];

\- (NSMutableDictionary \*)tasks\{

if (!\_tasks) \{

\_tasks = \[\[NSMutableDictionaryalloc\]init\];

return \_tasks;

// 请求头部,设置请求的数据大小

\- (void)requestHead:(NSMutableURLRequest \*)request path:(NSString \*)filePath\{

NSError \*error;

NSFileManager \*manager = \[NSFileManagerdefaultManager\];

NSDictionary \*attDic = \[manager  attributesOfItemAtPath:filePath error:&error\];

// 通过设置 rang的值，来处理是否已经下载完成或者还继续下载

NSString \*range = \[NSStringstringWithFormat:@"bytes=%zd-", \[\[attDic objectForKey:@"NSFileSize"\] integerValue\]\];

\[request setValue:range forHTTPHeaderField:@"Range"\];

// 文件判断

\- (NSString \*)fileCheck:(NSString \*)taskUrl\{

NSArray \*pathsArray =  NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, true);

NSString \*filePath = \[pathsArray  lastObject\];

filePath = \[filePath stringByAppendingPathComponent:\[taskUrl lastPathComponent\]\];

NSFileManager \*fileManager = \[NSFileManagerdefaultManager\];

bool isExists = \[fileManager  fileExistsAtPath:filePath\];

if (!isExists) \{

bool flag = \[fileManager  createFileAtPath:filePath contents:nil attributes:nil\];

if (flag) \{

NSLog(@"创建成功");

\}else\{

NSLog(@"创建失败");

return filePath;

\#pragma mark - 代理

\#pragma mark NSURLSessionDataDelegate

// 接受到响应

\- (void)URLSession:(NSURLSession \*)session dataTask:(NSURLSessionDataTask \*)dataTask didReceiveResponse:(NSHTTPURLResponse \*)response completionHandler:(void (^)(NSURLSessionResponseDisposition))completionHandler\{

\[\_stream open\];

// 获取这个文件的大小

\_fileTotalLength = \[response.allHeaderFields\[@"Content-Length"\] integerValue\];

// 接收这个请求，允许接收服务器的数据

completionHandler(NSURLSessionResponseAllow);

/\*\*

\* 接收到服务器返回的数据

\*/

\- (void)URLSession:(NSURLSession \*)session dataTask:(NSURLSessionDataTask \*)dataTask didReceiveData:(NSData \*)data\{

\[\_stream write:data.bytes maxLength:data.length\];

//  下载进度

NSError \*error;

NSFileManager \*manager = \[NSFileManagerdefaultManager\];

NSDictionary \*attDic = \[manager attributesOfItemAtPath:\[\_filePathArrayobjectAtIndex:\_index\] error:&error\];

NSUInteger receivedSize = \[\[attDic  objectForKey:@"NSFileSize"\]  integerValue\];

CGFloat progress =  1.0 \* receivedSize / \_fileTotalLength;

NSLog(@"当前进度\--%f",progress);

if (\_index == 0) \{

dispatch\_async(dispatch\_get\_main\_queue(), ^\{

\_progressView.progress = progress;

\});

\}else if(\_index == 1)\{

dispatch\_async(dispatch\_get\_main\_queue(), ^\{

\_secondPV.progress = progress;

\});

// 请求完毕（成功|失败）

\- (void)URLSession:(NSURLSession \*)session task:(NSURLSessionTask \*)task didCompleteWithError:(NSError \*)error\{

\[\_stream close\];

NSLog(@"文件下载成功");

\_index\++;

if (\_filePathArray.count > \_index) \{

\_stream = \[NSOutputStreamoutputStreamToFileAtPath:\[\_filePathArrayobjectAtIndex:\_index\] append:YES\];

NSURLSessionDataTask \*task = \[self getTask:\[\_urlArray objectAtIndex:\_index\]\];

\[task resume\];

// 开始下载

\- (IBAction)startAction:(id)sender \{

// 对应的文件需要对应的流处理。

\_stream = \[NSOutputStreamoutputStreamToFileAtPath:\[\_filePathArrayobjectAtIndex:\_index\] append:YES\];

NSURLSessionDataTask \*task = \[self getTask:\[\_urlArray objectAtIndex:\_index\]\];

\[task resume\];

// 停止下载

\- (IBAction)stopAction:(id)sender \{

NSURLSessionDataTask \*task = \[self getTask:\[\_urlArray objectAtIndex:\_index\]\];

\[task suspend\];

// 清理文件

\- (IBAction)cleanAction:(id)sender \{

NSFileManager \*manager = \[NSFileManagerdefaultManager\];

bool  flag = \[manager  fileExistsAtPath:\[\_filePathArray  objectAtIndex:\_index\]\];

if (flag) \{

bool removeFlag = \[manager  removeItemAtPath:\[\_filePathArray  objectAtIndex:\_index\]  error:nil\];

if (removeFlag) \{

NSLog(@"删除成功");

简单实现断点下载

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