File Download (large file download)

#import "SZMViewController.h"@interfaceSzmviewcontroller () <NSURLSessionDownloadDelegate>@end@implementationSzmviewcontroller- (void) viewdidload{[Super Viewdidload]; //additional setup after loading the view, typically from a nib.}//Task: Any request is a task//nsurlsessiondatatask: normal get\post request//nsurlsessiondownloadtask: File Download//nsurlsessionuploadtask: File Upload- (void) Touchesbegan: (Nsset *) touches withevent: (Uievent *)Event{[self downloadTask2];}- (void) downloadtask2{nsurlsessionconfiguration*cfg =[Nsurlsessionconfiguration defaultsessionconfiguration]; //1. Get the Session objectNsurlsession *session = [Nsurlsession sessionwithconfiguration:cfgDelegate: Self delegatequeue:[nsoperationqueue mainqueue]]; //2. Create a download taskNsurl *url = [Nsurl urlwithstring:@"Http://***********.mp4"]; Nsurlsessiondownloadtask*task =[Session Downloadtaskwithurl:url]; //3. Start a task[Task resume]; //If the download task is set Completionhandler this block, also implemented the download proxy method, priority to execute block}#pragmaMark-nsurlsessiondownloaddelegate/** * * @param the path of the location temp file (downloaded file) after download*/- (void) Urlsession: (Nsurlsession *) session Downloadtask: (Nsurlsessiondownloadtask *) downloadtask Didfinishdownloadingtourl: (Nsurl *) location{//Location: The path to the temporary file (downloaded file)NSString*caches =[Nssearchpathfordirectoriesindomains (Nscachesdirectory, Nsuserdomainmask, YES) lastobject]; //response.suggestedfilename: Recommended file name, generally consistent with server-side file nameNSString*file =[Caches stringByAppendingPathComponent:downloadTask.response.suggestedFilename]; //cut or copy a temporary file caches folderNsfilemanager *mgr =[Nsfilemanager Defaultmanager]; //atpath: File path before clipping//Topath: The file path after clipping[Mgr MoveItemAtPath:location.path topath:file error:nil];}/** * Restore when download is called*/- (void) Urlsession: (Nsurlsession *) session Downloadtask: (Nsurlsessiondownloadtask *) Downloadtask Didresumeatoffset: (int64_t) Fileoffset expectedtotalbytes: (int64_t) expectedtotalbytes{}/** * it will be called (may be called multiple times) whenever a portion of the download is finished (can be invoked more than once) * * @param byteswritten How much this call wrote * @param totalbyteswritten cumulative How many lengths were written to the sandbox? * @param total length of totalbytesexpectedtowrite file*/- (void) Urlsession: (Nsurlsession *) session Downloadtask: (Nsurlsessiondownloadtask *) Downloadtask Didwritedata: (int64_t) Byteswritten Totalbyteswritten: (int64_t) Totalbyteswritten Totalbytesexpectedtowrite: (int64_t) totalbytesexpectedtowrite{DoubleProgress = (Double) Totalbyteswritten/Totalbytesexpectedtowrite; NSLog (@"Download Progress---%f", progress);}#pragmaMark------------------------------------------------------------------/** Download task: Cannot see download progress*/- (void) downloadtask{//1. Get the Session objectNsurlsession *session =[Nsurlsession sharedsession]; //2. Create a download taskNsurl *url = [Nsurl urlwithstring:@"Http://localhost:****************test.mp4"]; Nsurlsessiondownloadtask*task = [Session Downloadtaskwithurl:url completionhandler:^ (Nsurl *location, Nsurlresponse *response, NSError *error) {        //Location: The path to the temporary file (downloaded file)NSString*caches =[Nssearchpathfordirectoriesindomains (Nscachesdirectory, Nsuserdomainmask, YES) lastobject]; //response.suggestedfilename: Recommended file name, generally consistent with server-side file nameNSString *file =[Caches stringByAppendingPathComponent:response.suggestedFilename]; //cut or copy a temporary file caches folderNsfilemanager *mgr =[Nsfilemanager Defaultmanager]; //atpath: File path before clipping//Topath: The file path after clipping[Mgr MoveItemAtPath:location.path topath:file Error:nil];        }]; //3. Start a task[Task resume];}- (void) datatask{//1. Get the Session objectNsurlsession *session =[Nsurlsession sharedsession]; //2. Create a task, tasks//Nsurl *url = [Nsurl urlwithstring:@]http://***********/video "]; //Nsurlsessiondatatask *task = [Session Datataskwithurl:url completionhandler:^ (NSData *data, Nsurlresponse *respons E, Nserror *error) {//nsdictionary *dict = [nsjsonserialization jsonobjectwithdata:data options:nsjsonreadingmutableleaves Error:nil    ]; //NSLog (@ "----%@", dict); //    }];Nsurl*url = [Nsurl urlwithstring:@"Http://192.168.**********/login"]; //Create a requestNsmutableurlrequest *request =[Nsmutableurlrequest Requestwithurl:url]; Request. HttpMethod=@"POST"; //set the request bodyRequest. Httpbody = [@"username=123&pwd=123"datausingencoding:nsutf8stringencoding]; Nsurlsessiondatatask*task = [Session datataskwithrequest:request completionhandler:^ (NSData *data, Nsurlresponse *response, NSError *error) {Nsdictionary*dict =[nsjsonserialization jsonobjectwithdata:data options:nsjsonreadingmutableleaves Error:nil]; NSLog (@"----%@", Dict);        }]; //3. Start a task[Task resume];}@end

File Download (large file download)