swift xcode IOS开发之——下载- NSURLSession(06)

一 概述

NSURLSessionDataTask:普通的Get\Post任务NSURLSessionDownloadTask:文件下载任务NSURLSessionUploadTask:文件上传

二 NSURLSessionDataTask

2.1 SessionDataTask-Get请求

-(void)URLTaskGet

{

NSURLSession *session=[NSURLSession sharedSession];

NSURL *url=[NSURL URLWithString:@"http://localhost:8080/MJServer/video"];

NSURLSessionDataTask *task= [session dataTaskWithURL:url completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {

//NSLog(@"%d",data.length);

NSDictionary *dict=[NSJSONSerialization JSONObjectWithData:data options:nil error:nil];

NSLog(@"%@",dict);

}];

//3-开始任务

[task resume];

}

2.2 SessionDataTask-Post请求

-(void)DataTaskPost

{

NSURLSession *session=[NSURLSession sharedSession];

NSURL *url=[NSURL URLWithString:@"http://localhost:8080/MJServer/login"];

NSMutableURLRequest *request=[NSMutableURLRequest requestWithURL:url];

request.HTTPMethod=@"POST";

NSString *param=[NSString stringWithFormat:@"username=%d&pwd=%d",123,123];

request.HTTPBody=[param dataUsingEncoding:NSUTF8StringEncoding];

NSURLSessionDataTask *task=[session dataTaskWithRequest:request completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {

NSDictionary *dict=[NSJSONSerialization JSONObjectWithData:data options:nil error:nil];

NSLog(@"%@",dict);

}];

//3-开始任务

[task resume];

}

三 NSURLSessionDownloadTask

3.1 downloadTaskWithURL

-(void)downloadTaskURL

{

//1-得到session对象

NSURLSession *session=[NSURLSession sharedSession];

//2-创建一个Task

NSURL *url=[NSURL URLWithString:@"http://localhost:8080/MJServer/resources/videos/minion_01.mp4"];

NSURLSessionDownloadTask *task= [session downloadTaskWithURL:url completionHandler:^(NSURL * _Nullable location, NSURLResponse * _Nullable response, NSError * _Nullable error) {

NSLog(@"下载完毕---%@",location);

//location:临时文件的路径(下载好的文件)

//将临时文件剪切或者复制caches文件夹

NSString *caches=[NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES)lastObject];

NSString *file=[caches stringByAppendingPathComponent:response.suggestedFilename];

NSFileManager *mgr=[NSFileManager defaultManager];

//AtPath:剪切前的文件路径

//toPath:剪切后的文件路径

[mgr moveItemAtPath:location.path toPath:file error:nil];

}];

//3-开始任务

[task resume];

}

3.2 downloadTaskWithURLNoHandler

//1-代理

@interface ViewController ()

@end

//2-task

-(void)downloadTaskWithURLNoHandler

{

NSURLSessionConfiguration *cfg=[NSURLSessionConfiguration defaultSessionConfiguration];

//得到session对象

NSURLSession *session=[NSURLSession sessionWithConfiguration:cfg delegate:self delegateQueue:[NSOperationQueue mainQueue]];

NSURL *url=[NSURL URLWithString:@"http://localhost:8080/MJServer/resources/videos/minion_01.mp4"];

//如果给下载任务设置了completionHandler这个block，也实现了下载的代理方法，优先执行block

NSURLSessionDownloadTask *task=[session downloadTaskWithURL:url];

// NSURLSessionDownloadTask *task=[session downloadTaskWithURL:url completionHandler:^(NSURL * _Nullable location, NSURLResponse * _Nullable response, NSError * _Nullable error) {

// NSLog(@"下载完毕");

//

// }];

//开始任务

[task resume];

}

//3-delegate

#pragma mark-NSURLSessionDownloadDelegate

//下载完毕

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

{

NSLog(@"下载didFinishDownloadingToURL--%@",location);

NSString *caches=[NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES)lastObject];

NSString *file=[caches stringByAppendingPathComponent:downloadTask.response.suggestedFilename];

NSFileManager *mgr=[NSFileManager defaultManager];

//AtPath:剪切前的文件路径

//toPath:剪切后的文件路径

[mgr moveItemAtPath:location.path toPath:file error:nil];

}

//恢复下载

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

{

}

//下载任务，写完一部分就调用

//bytesWritten：本次写了多少

//totalBytesWritten：累计写了多少长度到沙盒中

//totalBytesExpectedToWrite：文件的总长度

-(void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didWriteData:(int64_t)bytesWritten totalBytesWritten:(int64_t)totalBytesWritten totalBytesExpectedToWrite:(int64_t)totalBytesExpectedToWrite

{

double progress=(double)totalBytesWritten/totalBytesExpectedToWrite;

NSLog(@"下载进度--%f",progress);

}

3.3 效果图

相关链接

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