• NSURLSessionDownloadTask 断点下载



    #import "ViewController.h"

    #import "ASIHTTPRequest.h"

    #import <AFNetworking/AFNetworking.h>


    @interface ViewController () <NSURLSessionDownloadDelegate>


    @property (strong, nonatomic) NSURLSessionDownloadTask *resumableTask;   // 可恢复的下载任务


    @property (strong, nonatomic) NSURLSession *currentSession;    // 当前会话


    /* 用于可恢复的下载任务的数据 */

    @property (strong, nonatomic) NSData *partialData;


    @property (weak, nonatomic) IBOutlet UIProgressView *downloadingProgressView;

    @property (weak, nonatomic) IBOutlet UILabel *currentProgress_label;

    @end


    @implementation ViewController


    - (void)viewDidLoad {

        [super viewDidLoad];

        AFHTTPRequestOperationManager *man = [AFHTTPRequestOperationManager manager];

    }


    /* 创建当前的session */

    - (void)createCurrentSession {

        NSURLSessionConfiguration *defaultConfig = [NSURLSessionConfiguration defaultSessionConfiguration];

        self.currentSession = [NSURLSession sessionWithConfiguration:defaultConfig delegate:self delegateQueue:nil];

        self.currentSession.sessionDescription = @"fdfd";

    }


    - (IBAction)download:(id)sender {

        if (!self.currentSession) {

            [self createCurrentSession];

        }

        

        if (self.partialData) { // 假设是之前被暂停的任务,就从已经保存的数据恢复下载

            self.resumableTask = [self.currentSession downloadTaskWithResumeData:self.partialData];

        }

        else { // 否则创建下载任务

            NSString *imageURLStr = @"http://192.168.1.102/0701.zip";

            NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:imageURLStr]];

            self.resumableTask = [self.currentSession downloadTaskWithRequest:request];

        }

        

        [self.resumableTask resume];

        self.partialData = nil;

    }


    - (IBAction)stop:(id)sender {

        [self.resumableTask cancelByProducingResumeData:^(NSData *resumeData) {

            // 假设是可恢复的下载任务,应该先将数据保存到partialData中,注意在这里不要调用cancel方法

            self.partialData = resumeData;

            self.resumableTask = nil;

            NSLog(@"resumeData = %@", resumeData);

            

            [resumeData writeToFile:@"/Users/Mac/Desktop/resumeData" atomically:YES];

        }];

    }


    - (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didFinishDownloadingToURL:(NSURL *)location {

        NSLog(@"location = %@", location);

        

        // 设置文件的存放目标路径

        NSString *documentsPath = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES).firstObject;

        NSURL *documentsDirectoryURL = [NSURL fileURLWithPath:documentsPath];

        NSURL *fileURL = [documentsDirectoryURL URLByAppendingPathComponent:[[downloadTask.response URL] lastPathComponent]];

        

        // 假设该路径下文件已经存在。就要先将其移除,在移动文件

        NSFileManager *fileManager = [NSFileManager defaultManager];

        if ([fileManager fileExistsAtPath:[fileURL path] isDirectory:NULL]) {

            [fileManager removeItemAtURL:fileURL error:NULL];

        }

        [fileManager moveItemAtURL:location toURL:fileURL error:NULL];

    }


    /* fileOffset位移处恢复下载任务 */

    - (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didResumeAtOffset:(int64_t)fileOffset expectedTotalBytes:(int64_t)expectedTotalBytes {

        NSLog(@"NSURLSessionDownloadDelegate: Resume download at %lld", fileOffset);

    }


    /* 完毕下载任务,不管下载成功还是失败都调用该方法 */

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

        NSLog(@"NSURLSessionDownloadDelegate: Complete task");

        NSLog(@"下载失败:%@", error);

    }


    /* 运行下载任务时有数据写入 */

    - (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didWriteData:(int64_t)bytesWritten  totalBytesWritten:(int64_t)totalBytesWritten totalBytesExpectedToWrite:(int64_t)totalBytesExpectedToWrite // 期望收到的全部data字节数

    {

        // 计算当前下载进度并更新视图

        double downloadProgress = totalBytesWritten / (double)totalBytesExpectedToWrite;

        [self setDownloadProgress:downloadProgress];

    }


    /* 依据下载进度更新视图 */

    - (void)setDownloadProgress:(double)progress {

        

        NSString *progressStr = [NSString stringWithFormat:@"%.1f", progress * 100];

        progressStr = [progressStr stringByAppendingString:@"%"];

        

        NSLog(@"progressStr = %@", progressStr);

        

        dispatch_async(dispatch_get_main_queue(), ^{

            self.downloadingProgressView.progress = progress;

            self.currentProgress_label.text = progressStr;

        });

    }

    @end


    [self.currentSession downloadTaskWithResumeData:self.partialData];

    通过resumeData的原因例如以下是resumeData内容

    resumeData内容例如以下

    <?xml version="1.0" encoding="UTF-8"?

    >
    <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
    <plist version="1.0">
    <dict>
    <key>NSURLSessionDownloadURL</key>
    <string>http://192.168.1.102/0701.zip</string>
    <key>NSURLSessionResumeBytesReceived</key>
    <integer>47271936</integer>
    <key>NSURLSessionResumeCurrentRequest</key>
    <data>
    YnBsaXN0MDDUAQIDBAUGcnNYJHZlcnNpb25YJG9iamVjdHNZJGFyY2hpdmVyVCR0b3AS
    AAGGoK8QGAcIP0BGR05PUFFSU1Q1VVZiY2RlZmdobVUkbnVsbN8QGwkKCwwNDg8QERIT
    FBUWFxgZGhscHR4fICEiIyQlJicoKSUrLC0nLycmJiYkNTYmOCY6Jjw9PlMkMTJSJDNT
    JDI1UyQxN1IkNFMkMjFTJDEzViRjbGFzc1IkNVMkMThSJDZTJDIyUyQxNFIkN1MkMTlT
    JDEwUiQ4UiQwUyQxNVMkMjNSJDlTJDExUiQxUyQyNFMkMTZSJDJTJDIwgAiAAoAAgAeA
    A4AOgAKAF4AGgAyAB4APgAeAAIAAgACACBACgAqAAIAJgAAQCYAAgAsQFoANCNNBEEIm
    REVXTlMuYmFzZVtOUy5yZWxhdGl2ZYAAgAWABF8QHWh0dHA6Ly8xOTIuMTY4LjEuMTAy
    LzA3MDEuemlw0khJSktaJGNsYXNzbmFtZVgkY2xhc3Nlc1VOU1VSTKJMTVVOU1VSTFhO
    U09iamVjdCNATgAAAAAAABAACREBhCMAAAAAAAAAACMAAAAAAAAAABP//////////1NH
    RVTTV1gQWV1hV05TLmtleXNaTlMub2JqZWN0c6NaW1yAEIARgBKjXl9ggBOAFIAVgBZf
    EA9BY2NlcHQtRW5jb2RpbmdWQWNjZXB0XxAPQWNjZXB0LUxhbmd1YWdlXWd6aXAsIGRl
    ZmxhdGVTKi8qVWVuLXVz0khJaWpcTlNEaWN0aW9uYXJ5omtsXE5TRGljdGlvbmFyeVhO
    U09iamVjdNJISW5vXE5TVVJMUmVxdWVzdKJwcVxOU1VSTFJlcXVlc3RYTlNPYmplY3Rf
    EA9OU0tleWVkQXJjaGl2ZXLRdHVUcm9vdIABAAgAEQAaACMALQAyADcAUgBYAJEAlQCY
    AJwAoACjAKcAqwCyALUAuQC8AMAAxADHAMsAzwDSANUA2QDdAOAA5ADnAOsA7wDyAPYA
    +AD6APwA/gEAAQIBBAEGAQgBCgEMAQ4BEAESARQBFgEYARoBHAEeASABIgEkASYBKAEq
    ASwBLQE0ATwBSAFKAUwBTgFuAXMBfgGHAY0BkAGWAZ8BqAGqAasBrgG3AcAByQHNAdQB
    3AHnAesB7QHvAfEB9QH3AfkB+wH9Ag8CFgIoAjYCOgJAAkUCUgJVAmICawJwAn0CgAKN
    ApYCqAKrArAAAAAAAAACAQAAAAAAAAB2AAAAAAAAAAAAAAAAAAACsg==
    </data>
    <key>NSURLSessionResumeEntityTag</key>
    <string>"c04546-5c3ca3fe-5162cb9046b80"</string>
    <key>NSURLSessionResumeInfoLocalPath</key>
    <string>/Users/Mac/Library/Developer/CoreSimulator/Devices/E460928F-4469-41A7-B94E-8E6372A96C89/data/Containers/Data/Application/8E686354-BA1D-408E-8124-56AC07CD7287/tmp/CFNetworkDownload_brs2kY.tmp</string>
    <key>NSURLSessionResumeInfoVersion</key>
    <integer>1</integer>
    <key>NSURLSessionResumeOriginalRequest</key>
    <data>
    YnBsaXN0MDDUAQIDBAUGTk9YJHZlcnNpb25YJG9iamVjdHNZJGFyY2hpdmVyVCR0b3AS
    AAGGoK4HCDM0OjtCQ0RFRkdISVUkbnVsbN8QFQkKCwwNDg8QERITFBUWFxgZGhscHR4f
    ICEfIyQlICAoKCgeLC0uKDAxMlMkMTJSJDNTJDE3UiQ0UyQxM1YkY2xhc3NSJDVTJDE4
    UiQ2UyQxNFIkN1MkMTlTJDEwUiQ4UiQwUyQxNVIkOVMkMTFSJDFTJDE2UiQygAiAAoAH
    gAOAAoANgAaADIAHgAeAAIAAgACACBACgAqACYAAEAmACxAQCNM1DjYoODlXTlMuYmFz
    ZVtOUy5yZWxhdGl2ZYAAgAWABF8QHWh0dHA6Ly8xOTIuMTY4LjEuMTAyLzA3MDEuemlw
    0jw9Pj9aJGNsYXNzbmFtZVgkY2xhc3Nlc1VOU1VSTKJAQVVOU1VSTFhOU09iamVjdCNA
    TgAAAAAAABAACREBgCMAAAAAAAAAACMAAAAAAAAAABP//////////9I8PUpLXE5TVVJM
    UmVxdWVzdKJMTVxOU1VSTFJlcXVlc3RYTlNPYmplY3RfEA9OU0tleWVkQXJjaGl2ZXLR
    UFFUcm9vdIABAAgAEQAaACMALQAyADcARgBMAHkAfQCAAIQAhwCLAJIAlQCZAJwAoACj
    AKcAqwCuALEAtQC4ALwAvwDDAMYAyADKAMwAzgDQANIA1ADWANgA2gDcAN4A4ADiAOQA
    5gDoAOoA7ADuAPAA8QD4AQABDAEOARABEgEyATcBQgFLAVEBVAFaAWMBbAFuAW8BcgF7
    AYQBjQGSAZ8BogGvAbgBygHNAdIAAAAAAAACAQAAAAAAAABSAAAAAAAAAAAAAAAAAAAB
    1A==
    </data>
    <key>NSURLSessionResumeServerDownloadDate</key>
    <string>Sat, 16 May 2015 06:03:42 GMT</string>
    </dict>
    </plist>

    版权声明:本文博主原创文章,博客,未经同意不得转载。

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  • 原文地址:https://www.cnblogs.com/hrhguanli/p/4913722.html
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