NSURLSession详解
导语
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现在NSURLConnection在开发中会使用的越来越少，iOS9已经将NSURLConnection废弃，现在最低版本一般适配iOS7，所以也可以使用。
- NSURLConnection相对于NSURLSession,安全性低。NSURLConnection下载有峰值，比较麻烦处理。
- 尽管适配最低版本iOS7，也可以使用NSURLSession。AFN已经不支持NSURLConnection。
- NSURLSession：默认是挂起状态，如果要请求网络，需要开启。
[NSURLSession sharedSession] 获取全局的NSURLSession对象。在iPhone的所有app共用一个全局session.
NSURLSessionUploadTask -> NSURLSessionDataTask -> NSURLSessionTask
NSURLSessionDownloadTask -> NSURLSessionTask
NSURLSessionDownloadTask下载，默认下载到tmp文件夹。下载完成后删除临时文件。所以我们要在删除文件之前，将它移动到Cache里。
NSURLSession详解
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NSURLSession基础
- NSURLSession代理
- NSURLSession大文件下载
- NSURLSession断点续传
1.NSURLSession基础
- 第一种网络请求方法
//创建URL NSURL * url = [NSURL URLWithString:@"http://192.168.1.200/login.php?username=haha&password=123"]; //创建请求 // NSURLRequest * request = [NSURLRequest requestWithURL:url]; //创建Session NSURLSession * session = [NSURLSession sharedSession]; //创建任务 NSURLSessionDataTask * task = [session dataTaskWithURL:url completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) { NSLog(@"%@",[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]); }]; //开启网络任务 [task resume];
- 第二种网络请求方法
//创建URL NSURL * url = [NSURL URLWithString:@"http://192.168.1.200/login.php?username=haha&password=123"]; //创建请求 NSURLRequest * request = [NSURLRequest requestWithURL:url]; //创建Session NSURLSession * session = [NSURLSession sharedSession]; //创建任务 NSURLSessionDataTask * task = [session dataTaskWithRequest:request completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) { NSLog(@"%@",[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]); }]; //开启网络任务 [task resume];
- POST请求
NSURL * url = [NSURL URLWithString:@"http://192.168.1.200/login.php"]; NSMutableURLRequest * request = [NSMutableURLRequest requestWithURL:url]; //设置请求方法 request.HTTPMethod = @"POST"; //设置请求体 request.HTTPBody = [@"username=haha&password=123" dataUsingEncoding:NSUTF8StringEncoding]; [[[NSURLSession sharedSession] dataTaskWithRequest:request completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) { NSLog(@"%@",[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]); }] resume];
- 下载文件
NSURL * url = [NSURL URLWithString:[@"http://192.168.1.200/DOM解析.mp4" stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]]; NSURLSession * session = [NSURLSession sharedSession]; NSURLSessionDownloadTask * downloadTask = [session downloadTaskWithURL:url completionHandler:^(NSURL * _Nullable location, NSURLResponse * _Nullable response, NSError * _Nullable error) { //location 下载到沙盒的地址 NSLog(@"下载完成%@",location); //response.suggestedFilename 响应信息中的资源文件名 NSString * cachesPath = [[NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:response.suggestedFilename]; NSLog(@"缓存地址%@",cachesPath); //获取文件管理器 NSFileManager * mgr = [NSFileManager defaultManager]; //将临时文件移动到缓存目录下 //[NSURL fileURLWithPath:cachesPath] 将本地路径转化为URL类型 //URL如果地址不正确，生成的url对象为空 [mgr moveItemAtURL:location toURL:[NSURL fileURLWithPath:cachesPath] error:NULL]; }]; [downloadTask resume];
2.NSURLSession代理
- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event { // 全局session // NSURLSession * session = [NSURLSession sharedSession]; //创建自定义session //NSURLSessionConfiguration 的 配置 //[[NSOperationQueue alloc] init] 也可以写成 nil NSURL * url = [NSURL URLWithString:@"http://192.168.1.200/login.php?username=haha&password=123"]; NSURLSession * session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration] delegate:self delegateQueue:[[NSOperationQueue alloc] init]]; NSURLSessionDataTask * task = [session dataTaskWithURL:url]; [task resume]; } //接收到服务器响应 - (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveResponse:(NSURLResponse *)response completionHandler:(void (^)(NSURLSessionResponseDisposition disposition))completionHandler { NSLog(@"%s",__FUNCTION__); //允许接受服务器回传数据 completionHandler(NSURLSessionResponseAllow); } //接收服务器回传的数据,有可能执行多次 - (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveData:(NSData *)data { NSLog(@"%@",[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]); } //请求成功或失败 - (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error { NSLog(@"%@",error); }
3.NSURLSession大文件下载
#import "ViewController.h" @interface ViewController ()<NSURLSessionDownloadDelegate> @end @implementation ViewController - (void)viewDidLoad { [super viewDidLoad]; // Do any additional setup after loading the view, typically from a nib. NSLog(@"%@",NSSearchPathForDirectoriesInDomains(9, 1, 1)); } - (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event { NSURLSession * session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration] delegate:self delegateQueue:[[NSOperationQueue alloc] init]]; NSURLSessionDownloadTask * task = [session downloadTaskWithURL:[NSURL URLWithString:[@"http://192.168.1.200/DOM解析.mp4"stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]]]; [task resume]; } /* 监测临时文件下载的数据大小，当每次写入临时文件时，就会调用一次 bytesWritten 单次写入多少 totalBytesWritten 已经写入了多少 totalBytesExpectedToWrite 文件总大小 */ - (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didWriteData:(int64_t)bytesWritten totalBytesWritten:(int64_t)totalBytesWritten totalBytesExpectedToWrite:(int64_t)totalBytesExpectedToWrite { //打印下载百分比 NSLog(@"%f",totalBytesWritten * 1.0 / totalBytesExpectedToWrite); } //下载完成 - (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didFinishDownloadingToURL:(NSURL *)location { NSString * cachesPath = [[NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:downloadTask.response.suggestedFilename]; NSFileManager * mgr = [NSFileManager defaultManager]; [mgr moveItemAtURL:location toURL:[NSURL fileURLWithPath:cachesPath] error:NULL]; } - (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error { NSLog(@"%@",error); }
4.NSURLSession断点续传
#import "ViewController.h" @interface ViewController ()<NSURLSessionDownloadDelegate> @property (nonatomic, strong) NSURLSessionDownloadTask * task; @property (nonatomic, strong) NSData * resumeData; @property (nonatomic, strong) NSURLSession * session; @end @implementation ViewController //故事板中开始按钮的响应方法 - (IBAction)start:(id)sender { NSURLSession * session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration] delegate:self delegateQueue:[[NSOperationQueue alloc] init]]; self.session = session; self.task = [session downloadTaskWithURL:[NSURL URLWithString:[@"http://192.168.1.68/丁香花.mp3"stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]]]; [self.task resume]; } //故事板中暂停按钮的响应方法 - (IBAction)pause:(id)sender { //暂停就是将任务挂起 [self.task cancelByProducingResumeData:^(NSData *resumeData) { //保存已下载的数据 self.resumeData = resumeData; }]; } //继续按钮的响应方法 - (IBAction)resume:(id)sender { //可以使用ResumeData创建任务 self.task = [self.session downloadTaskWithResumeData:self.resumeData]; //开启继续下载 [self.task resume]; } - (void)viewDidLoad { [super viewDidLoad]; // Do any additional setup after loading the view, typically from a nib. NSLog(@"%@",NSSearchPathForDirectoriesInDomains(9, 1, 1)); } /* 监测临时文件下载的数据大小，当每次写入临时文件时，就会调用一次 bytesWritten 单次写入多少 totalBytesWritten 已经写入了多少 totalBytesExpectedToWrite 文件总大小 */ - (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didWriteData:(int64_t)bytesWritten totalBytesWritten:(int64_t)totalBytesWritten totalBytesExpectedToWrite:(int64_t)totalBytesExpectedToWrite { //打印下载百分比 NSLog(@"%f",totalBytesWritten * 1.0 / totalBytesExpectedToWrite); } //下载完成 - (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didFinishDownloadingToURL:(NSURL *)location { NSString * cachesPath = [[NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:downloadTask.response.suggestedFilename]; NSFileManager * mgr = [NSFileManager defaultManager]; [mgr moveItemAtURL:location toURL:[NSURL fileURLWithPath:cachesPath] error:NULL]; } - (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error { NSLog(@"%@",error); }