iOS实现断点续传

NSURLConnection 实现断点续传

controller

//写文件的文件句柄
@property (nonatomic,strong) NSFileHandle *writeHandle;

//当前下载总的字节数
@property (nonatomic) long long currentDownloadByte;

//总文件大小
@property (nonatomic) CGFloat fileSize;

@end

@implementation ViewController
{
NSURLConnection *conn;
}

• (void)viewDidLoad {
  [super viewDidLoad];
  // Do any additional setup after loading the view, typically from a nib.
  NSLog(@”%@”,[self getFilePath]);

  //本地文件大小
  NSDictionary *fileInfo = [[NSFileManager defaultManager] attributesOfItemAtPath:[self getFilePath] error:nil];

  self.currentDownloadByte = fileInfo.fileSize;
  self.fileSize = [[[NSUserDefaults standardUserDefaults] objectForKey:@”fileSize”] floatValue];

  if(self.fileSize != 0)
  {
  self.proView.progress = self.currentDownloadByte / self.fileSize;
  self.proLabel.text = [NSString stringWithFormat:@”%.2f%%”,self.proView.progress * 100];
  }
  }

• (IBAction)pause:(id)sender {
  //暂停下载
  [conn cancel];

  //文件关闭
  [self.writeHandle closeFile];
  }

//文件操作 NSFileHandle —-> 沙盒
-(NSString *)getFilePath
{
return [NSString stringWithFormat:@”%@/Documents/qq.dmg”,NSHomeDirectory()];
}

• (IBAction)start:(id)sender {
  NSURL *url = [NSURL URLWithString:KCYQQURL];

  NSMutableURLRequest *req = [NSMutableURLRequest requestWithURL:url];

  //Range
  //告诉服务器 下载数据范围
  [req setValue:[NSString stringWithFormat:@”bytes=%lld-“,self.currentDownloadByte] forHTTPHeaderField:@”Range”];

  conn = [[NSURLConnection alloc] initWithRequest:req delegate:self];
  }

-(void)connection:(NSURLConnection )connection didReceiveResponse:(NSURLResponse )response
{
//得到文件大小
self.fileSize = response.expectedContentLength + self.currentDownloadByte;

[[NSUserDefaults standardUserDefaults] setObject:[NSNumber numberWithFloat:self.fileSize] forKey:@"fileSize"];[[NSUserDefaults standardUserDefaults] synchronize];//创建文件if(![[NSFileManager defaultManager] fileExistsAtPath:[self getFilePath]]){    [[NSFileManager defaultManager] createFileAtPath:[self getFilePath] contents:nil attributes:nil];}//打开文件  -->  文件指针 默认指向文件头部self.writeHandle = [NSFileHandle fileHandleForWritingAtPath:[self getFilePath]];//把文件指针指向文件的尾部[self.writeHandle seekToEndOfFile];

}

-(void)connection:(NSURLConnection )connection didReceiveData:(NSData )data
{
//把数据写入到文件
[self.writeHandle writeData:data];

self.currentDownloadByte += data.length;self.proView.progress = self.currentDownloadByte / self.fileSize;self.proLabel.text = [NSString stringWithFormat:@"%.2f%%",self.proView.progress * 100];

}

-(void)connectionDidFinishLoading:(NSURLConnection *)connection
{
//关闭文件
[self.writeHandle closeFile];
}

NSURLSeesion 实现断点续传

@property (nonatomic,strong) NSURLSession *session;

@property (nonatomic,strong) NSURLSessionDownloadTask *downloadTask;

@end

@implementation ViewController

• (void)viewDidLoad {
  [super viewDidLoad];
  // Do any additional setup after loading the view, typically from a nib.

  self.session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration] delegate:self delegateQueue:[NSOperationQueue mainQueue]];
  }

-(void)URLSession:(NSURLSession )session downloadTask:(NSURLSessionDownloadTask )downloadTask didWriteData:(int64_t)bytesWritten totalBytesWritten:(int64_t)totalBytesWritten totalBytesExpectedToWrite:(int64_t)totalBytesExpectedToWrite
{
self.proView.progress = totalBytesWritten / (CGFloat)totalBytesExpectedToWrite;
self.proLabel.text = [NSString stringWithFormat:@”%.2f%%”,self.proView.progress * 100];
}

//下载完成的方法 —> 处理下载完成的文件
//location 当前下载数据的缓存文件路径
-(void)URLSession:(NSURLSession )session downloadTask:(NSURLSessionDownloadTask )downloadTask didFinishDownloadingToURL:(NSURL *)location
{
//把文件复制到自己的文件夹里

NSString *qqPath = [NSString stringWithFormat:@"%@/Documents/qq.dmg",NSHomeDirectory()];if(![[NSFileManager defaultManager] fileExistsAtPath:qqPath]){    [[NSFileManager defaultManager] copyItemAtURL:location toURL:[NSURL fileURLWithPath:qqPath] error:nil];}

}

• (void)didReceiveMemoryWarning {
  [super didReceiveMemoryWarning];
  // Dispose of any resources that can be recreated.
  }

• (IBAction)pause:(id)sender {

  //暂停下载
  //resumeData 暂停之前 所有下载的数据
  [self.downloadTask cancelByProducingResumeData:^(NSData * _Nullable resumeData) {
  [[NSUserDefaults standardUserDefaults] setObject:resumeData forKey:@”resumeData”];
  [[NSUserDefaults standardUserDefaults] synchronize];
  }];
  }

• (IBAction)start:(id)sender {
  NSURLRequest *req = [NSURLRequest requestWithURL:[NSURL URLWithString:@”http://dldir1.qq.com/qqfile/QQforMac/QQ_V4.0.1.dmg“]];

  NSData *data = [[NSUserDefaults standardUserDefaults] objectForKey:@”resumeData”];

  if(data.length == 0)
  {
  self.downloadTask = [self.session downloadTaskWithRequest:req];
  }
  else
  {
  self.downloadTask = [self.session downloadTaskWithResumeData:data];
  }

  [self.downloadTask resume];
  }