iOS网络(四)：NSURLSession的使用，断点下载，离线断点续传，上传文件

NSURLSession

使用步骤

使用NSURLSession对象创建Task，然后执行Task

Task的类型

NSURLSession的基本使用步骤代码：

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
    [self post];
}

-(void)get
{
    //1.确定URL
    NSURL *url = [NSURL URLWithString:@"http://120.25.226.186:32812/login?username=Alan&pwd=123&type=JSON"];
    
    //2.创建请求对象
    NSURLRequest *request =[NSURLRequest requestWithURL:url];
    
    //3.创建会话对象
    NSURLSession *session = [NSURLSession sharedSession];
    
    //4.创建Task
    /*
     第一个参数:请求对象
     第二个参数:completionHandler 当请求完成之后调用
        data:响应体信息
        response:响应头信息
        error:错误信息当请求失败的时候 error有值
     */
    NSURLSessionDataTask *dataTask = [session dataTaskWithRequest:request completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
        
        //6.解析数据
        NSLog(@"%@",[[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding]);
    }];
    
    //5.执行Task
    [dataTask resume];
}

-(void)get2
{
    //1.确定URL
    NSURL *url = [NSURL URLWithString:@"http://120.25.226.186:32812/login?username=Alan&pwd=123&type=JSON"];
    
    //2.创建请求对象
    //NSURLRequest *request =[NSURLRequest requestWithURL:url];
    
    //3.创建会话对象
    NSURLSession *session = [NSURLSession sharedSession];
    
    //4.创建Task
    /*
     第一个参数:请求路径
     第二个参数:completionHandler 当请求完成之后调用
     data:响应体信息
     response:响应头信息
     error:错误信息当请求失败的时候 error有值
     注意:dataTaskWithURL 内部会自动的将请求路径作为参数创建一个请求对象(GET)
     */
    NSURLSessionDataTask *dataTask = [session dataTaskWithURL:url completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
        
        //6.解析数据
        NSLog(@"%@",[[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding]);
    }];
    
    //5.执行Task
    [dataTask resume];
}

-(void)post
{
    //1.确定URL
    NSURL *url = [NSURL URLWithString:@"http://120.25.226.186:32812/login"];
    
    //2.创建请求对象
    NSMutableURLRequest *request =[NSMutableURLRequest requestWithURL:url];
    
    //2.1 设置请求方法为post
    request.HTTPMethod = @"POST";
    
    //2.2 设置请求体
    request.HTTPBody = [@"username=Alan&pwd=123&type=JSON" dataUsingEncoding:NSUTF8StringEncoding];
    
    //3.创建会话对象
    NSURLSession *session = [NSURLSession sharedSession];
    
    //4.创建Task
    /*
     第一个参数:请求对象
     第二个参数:completionHandler 当请求完成之后调用 !!! 在子线程中调用
     data:响应体信息
     response:响应头信息
     error:错误信息当请求失败的时候 error有值
     */
    NSURLSessionDataTask *dataTask = [session dataTaskWithRequest:request completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
        
        NSLog(@"%@",[NSThread currentThread]);
        //6.解析数据
        NSLog(@"%@",[[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding]);
    }];
    
    //5.执行Task
    [dataTask resume];
}

@end

注意： completionHandler 当请求完成之后调用 !!! 在子线程中调用。所以如果有更新UI操作，请调回主线程。

NSURLSession使用代理下载一个文件：

#import "ViewController.h"

@interface ViewController ()<NSURLSessionDataDelegate>
/** 接受响应体信息 */
@property (nonatomic, strong) NSMutableData *fileData;
@end

@implementation ViewController

-(NSMutableData *)fileData
{
    if (_fileData == nil) {
        _fileData = [NSMutableData data];
    }
    return _fileData;
}
-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
    //1.url
    NSURL *url = [NSURL URLWithString:@"http://f.hiphotos.baidu.com/zhidao/pic/item/86d6277f9e2f07084d0cac07e924b899a901f2a8.jpg"];
    
    //2.创建请求对象
    NSURLRequest *request = [NSURLRequest requestWithURL:url];
    
    //3.创建会话对象,设置代理
    /*
     第一个参数:配置信息 [NSURLSessionConfiguration defaultSessionConfiguration]
     第二个参数:代理
     第三个参数:设置代理方法在哪个线程中调用
     */
    NSURLSession *session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration] delegate:self delegateQueue:[NSOperationQueue mainQueue]];
    
    //4.创建Task
    NSURLSessionDataTask *dataTask = [session dataTaskWithRequest:request];
    
    //5.执行Task
    [dataTask resume];
}

#pragma mark ----------------------
#pragma mark NSURLSessionDataDelegate
/**
 *  1.接收到服务器的响应 它默认会取消该请求
 *
 *  @param session           会话对象
 *  @param dataTask          请求任务
 *  @param response          响应头信息
 *  @param completionHandler 回调 传给系统
 */
-(void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveResponse:(NSURLResponse *)response completionHandler:(void (^)(NSURLSessionResponseDisposition))completionHandler
{
    NSLog(@"%s",__func__);
    
    /*
     NSURLSessionResponseCancel = 0,取消 默认
     NSURLSessionResponseAllow = 1, 接收
     NSURLSessionResponseBecomeDownload = 2, 变成下载任务
     NSURLSessionResponseBecomeStream        变成流
     */
    completionHandler(NSURLSessionResponseAllow);
}

/**
 *  接收到服务器返回的数据 调用多次
 *
 *  @param session           会话对象
 *  @param dataTask          请求任务
 *  @param data              本次下载的数据
 */
-(void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveData:(NSData *)data
{
     NSLog(@"%s",__func__);
    
    //拼接数据
    [self.fileData appendData:data];
}

/**
 *  请求结束或者是失败的时候调用
 *
 *  @param session           会话对象
 *  @param dataTask          请求任务
 *  @param error             错误信息
 */
-(void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error
{
     NSLog(@"%s",__func__);
    
    //解析数据
    NSLog(@"%@",[[NSString alloc]initWithData:self.fileData encoding:NSUTF8StringEncoding]);
}


@end

NSURLSessionDownloadTask断点下载

#import "ViewController.h"

@interface ViewController ()<NSURLSessionDownloadDelegate>
@property (nonatomic, strong) NSURLSessionDownloadTask *downloadTask;
@property (nonatomic, strong) NSData *resumData;
@property (nonatomic, strong) NSURLSession *session;
@end

@implementation ViewController

- (IBAction)startBtnClick:(id)sender
{
    //1.url
    NSURL *url = [NSURL URLWithString:@"http://f.hiphotos.baidu.com/zhidao/pic/item/86d6277f9e2f07084d0cac07e924b899a901f2a8.jpg"];
    
    //2.创建请求对象
    NSURLRequest *request = [NSURLRequest requestWithURL:url];
    
    //3.创建session
    NSURLSessionConfiguration *config = [NSURLSessionConfiguration defaultSessionConfiguration];
    self.session = [NSURLSession sessionWithConfiguration:config delegate:self delegateQueue:[NSOperationQueue mainQueue]];
    
    //4.创建Task
    NSURLSessionDownloadTask *downloadTask = [self.session downloadTaskWithRequest:request];
    
    //5.执行Task
    [downloadTask resume];
    
    self.downloadTask = downloadTask;

}

//暂停是可以恢复
- (IBAction)suspendBtnClick:(id)sender
{
    NSLog(@"+++++++++++++++++++暂停");
    [self.downloadTask suspend];
}

//cancel:取消是不能恢复
//cancelByProducingResumeData:是可以恢复
- (IBAction)cancelBtnClick:(id)sender
{
    NSLog(@"+++++++++++++++++++取消");
    //[self.downloadTask cancel];
    
    //恢复下载的数据!=文件数据
    [self.downloadTask cancelByProducingResumeData:^(NSData * _Nullable resumeData) {
        //resumeData表示的不是文件下载大小，而是下载到哪个字节数据
        self.resumData = resumeData;
    }];
}

- (IBAction)goOnBtnClick:(id)sender
{
    NSLog(@"+++++++++++++++++++恢复下载");
    //取消后继续下载
    if(self.resumData)
    {
        self.downloadTask = [self.session downloadTaskWithResumeData:self.resumData];
    }
    //暂停后下载
    [self.downloadTask resume];
}

#pragma mark ----------------------
#pragma mark NSURLSessionDownloadDelegate
/**
 *  写数据
 *
 *  @param session                   会话对象
 *  @param downloadTask              下载任务
 *  @param bytesWritten              本次写入的数据大小
 *  @param totalBytesWritten         下载的数据总大小
 *  @param totalBytesExpectedToWrite  文件的总大小
 */
-(void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didWriteData:(int64_t)bytesWritten totalBytesWritten:(int64_t)totalBytesWritten totalBytesExpectedToWrite:(int64_t)totalBytesExpectedToWrite
{
    //1. 获得文件的下载进度
    NSLog(@"%f",1.0 * totalBytesWritten/totalBytesExpectedToWrite);
}

/**
 *  当恢复下载的时候调用该方法
 *
 *  @param fileOffset         从什么地方下载
 *  @param expectedTotalBytes 文件的总大小
 */
-(void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didResumeAtOffset:(int64_t)fileOffset expectedTotalBytes:(int64_t)expectedTotalBytes
{
    NSLog(@"%s",__func__);
}

/**
 *  当下载完成的时候调用
 *
 *  @param location     文件的临时存储路径
 */
-(void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didFinishDownloadingToURL:(NSURL *)location
{
    NSLog(@"%@",location);
    
    //1 拼接文件全路径
    NSString *fullPath = [[NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:downloadTask.response.suggestedFilename];
    
    //2 剪切文件
    [[NSFileManager defaultManager]moveItemAtURL:location toURL:[NSURL fileURLWithPath:fullPath] error:nil];
    NSLog(@"%@",fullPath);
}

/**
 *  请求结束
 */
-(void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error
{
    NSLog(@"didCompleteWithError");
}

@end

NSURLSessionDataTask结合NSFileHandle实现断点下载

#import "ViewController.h"

@interface ViewController ()<NSURLSessionDataDelegate>
@property (weak, nonatomic) IBOutlet UIProgressView *proessView;
/** 接受响应体信息 */
@property (nonatomic, strong) NSFileHandle *handle;
@property (nonatomic, assign) NSInteger totalSize;
@property (nonatomic, assign) NSInteger currentSize;
@property (nonatomic, strong) NSString *fullPath;
@end

@implementation ViewController

-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
    //1.url
    NSURL *url = [NSURL URLWithString:@"http://v.baidu.com/watch/2211980252341948619.html?&page=videoMultiNeed"];
    
    //2.创建请求对象
    NSURLRequest *request = [NSURLRequest requestWithURL:url];
    
    //3.创建会话对象,设置代理
    /*
     第一个参数:配置信息 [NSURLSessionConfiguration defaultSessionConfiguration]
     第二个参数:代理
     第三个参数:设置代理方法在哪个线程中调用
     */
    NSURLSession *session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration] delegate:self delegateQueue:[NSOperationQueue mainQueue]];
    
    //4.创建Task
    NSURLSessionDataTask *dataTask = [session dataTaskWithRequest:request];
    
    //5.执行Task
    [dataTask resume];
}

#pragma mark ----------------------
#pragma mark NSURLSessionDataDelegate
/**
 *  1.接收到服务器的响应 它默认会取消该请求
 *
 *  @param session           会话对象
 *  @param dataTask          请求任务
 *  @param response          响应头信息
 *  @param completionHandler 回调 传给系统
 */
-(void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveResponse:(NSURLResponse *)response completionHandler:(void (^)(NSURLSessionResponseDisposition))completionHandler
{
    //获得文件的总大小
    self.totalSize = response.expectedContentLength;
    
    //获得文件全路径
    self.fullPath = [[NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:response.suggestedFilename];
    
    //创建空的文件
    [[NSFileManager defaultManager]createFileAtPath:self.fullPath contents:nil attributes:nil];
    
    //创建文件句柄
    self.handle = [NSFileHandle fileHandleForWritingAtPath:self.fullPath];
    
    [self.handle seekToEndOfFile];
    /*
     NSURLSessionResponseCancel = 0,取消 默认
     NSURLSessionResponseAllow = 1, 接收
     NSURLSessionResponseBecomeDownload = 2, 变成下载任务
     NSURLSessionResponseBecomeStream        变成流
     */
    completionHandler(NSURLSessionResponseAllow);
}

/**
 *  接收到服务器返回的数据 调用多次
 *
 *  @param session           会话对象
 *  @param dataTask          请求任务
 *  @param data              本次下载的数据
 */
-(void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveData:(NSData *)data
{
    
    //写入数据到文件
    [self.handle writeData:data];
    
    //计算文件的下载进度
    self.currentSize += data.length;
    NSLog(@"%f",1.0 * self.currentSize / self.totalSize);
    
    self.proessView.progress = 1.0 * self.currentSize / self.totalSize;
}

/**
 *  请求结束或者是失败的时候调用
 *
 *  @param session           会话对象
 *  @param dataTask          请求任务
 *  @param error             错误信息
 */
-(void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error
{
    NSLog(@"%@",self.fullPath);
    
    //关闭文件句柄
    [self.handle closeFile];
    self.handle = nil;
}


@end

NSURLSessionDataTask离线断点续传(退出App后打开继续下载)

#import "ViewController.h"
#define FileName @"121212.mp4"

@interface ViewController ()<NSURLSessionDataDelegate>
@property (weak, nonatomic) IBOutlet UIProgressView *proessView;
/** 接受响应体信息 */
@property (nonatomic, strong) NSFileHandle *handle;
@property (nonatomic, assign) NSInteger totalSize;
@property (nonatomic, assign) NSInteger currentSize;
@property (nonatomic, strong) NSString *fullPath;
@property (nonatomic, strong)  NSURLSessionDataTask *dataTask;
@property (nonatomic, strong) NSURLSession *session;

@end

@implementation ViewController

-(void)viewDidLoad
{
    [super viewDidLoad];
    
    //1.读取保存的文件总大小的数据,0
    //2.获得当前已经下载的数据的大小
    //3.计算得到进度信息
    
}
-(NSString *)fullPath
{
    if (_fullPath == nil) {
        
        //获得文件全路径
        _fullPath = [[NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:FileName];
    }
    return _fullPath;
}

-(NSURLSession *)session
{
    if (_session == nil) {
        //3.创建会话对象,设置代理
        /*
         第一个参数:配置信息 [NSURLSessionConfiguration defaultSessionConfiguration]
         第二个参数:代理
         第三个参数:设置代理方法在哪个线程中调用
         */
        _session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration] delegate:self delegateQueue:[NSOperationQueue mainQueue]];
    }
    return _session;
}
-(NSURLSessionDataTask *)dataTask
{
    if (_dataTask == nil) {
        //1.url
        NSURL *url = [NSURL URLWithString:@"http://120.25.226.186:32812/resources/videos/minion_01.mp4"];
        
        //2.创建请求对象
        NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
        
        //3 设置请求头信息,告诉服务器请求那一部分数据
        self.currentSize = [self getFileSize];
        NSString *range = [NSString stringWithFormat:@"bytes=%zd-",self.currentSize];
        [request setValue:range forHTTPHeaderField:@"Range"];
        
        //4.创建Task
        _dataTask = [self.session dataTaskWithRequest:request];
    }
    return _dataTask;
}

-(NSInteger)getFileSize
{
    //获得指定文件路径对应文件的数据大小
    NSDictionary *fileInfoDict = [[NSFileManager defaultManager]attributesOfItemAtPath:self.fullPath error:nil];
    NSLog(@"%@",fileInfoDict);
    NSInteger currentSize = [fileInfoDict[@"NSFileSize"] integerValue];
    
    return currentSize;
}
- (IBAction)startBtnClick:(id)sender
{
    [self.dataTask resume];
}

- (IBAction)suspendBtnClick:(id)sender
{
    NSLog(@"_________________________suspend");
    [self.dataTask suspend];
}

//注意:dataTask的取消是不可以恢复的
- (IBAction)cancelBtnClick:(id)sender
{
      NSLog(@"_________________________cancel");
    [self.dataTask cancel];
    self.dataTask = nil;
}

- (IBAction)goOnBtnClick:(id)sender
{
      NSLog(@"_________________________resume");
    [self.dataTask resume];
}

#pragma mark ----------------------
#pragma mark NSURLSessionDataDelegate
/**
 *  1.接收到服务器的响应 它默认会取消该请求
 *
 *  @param session           会话对象
 *  @param dataTask          请求任务
 *  @param response          响应头信息
 *  @param completionHandler 回调 传给系统
 */
-(void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveResponse:(NSURLResponse *)response completionHandler:(void (^)(NSURLSessionResponseDisposition))completionHandler
{
    //获得文件的总大小
    //expectedContentLength 本次请求的数据大小
    self.totalSize = response.expectedContentLength + self.currentSize;
    
    if (self.currentSize == 0) {
        //创建空的文件
        [[NSFileManager defaultManager]createFileAtPath:self.fullPath contents:nil attributes:nil];
        
    }
    //创建文件句柄
    self.handle = [NSFileHandle fileHandleForWritingAtPath:self.fullPath];
    
    //移动指针
    [self.handle seekToEndOfFile];
    
    /*
     NSURLSessionResponseCancel = 0,取消 默认
     NSURLSessionResponseAllow = 1, 接收
     NSURLSessionResponseBecomeDownload = 2, 变成下载任务
     NSURLSessionResponseBecomeStream        变成流
     */
    completionHandler(NSURLSessionResponseAllow);
}

/**
 *  接收到服务器返回的数据 调用多次
 *
 *  @param session           会话对象
 *  @param dataTask          请求任务
 *  @param data              本次下载的数据
 */
-(void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveData:(NSData *)data
{
    
    //写入数据到文件
    [self.handle writeData:data];
    
    //计算文件的下载进度
    self.currentSize += data.length;
    NSLog(@"%f",1.0 * self.currentSize / self.totalSize);
    
    self.proessView.progress = 1.0 * self.currentSize / self.totalSize;
}

/**
 *  请求结束或者是失败的时候调用
 *
 *  @param session           会话对象
 *  @param dataTask          请求任务
 *  @param error             错误信息
 */
-(void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error
{
    NSLog(@"%@",self.fullPath);
    
    //关闭文件句柄
    [self.handle closeFile];
    self.handle = nil;
}

-(void)dealloc
{
    //清理工作
    //finishTasksAndInvalidate
    [self.session invalidateAndCancel];
}

@end

NSURLSession实现文件上传(NSURLSessionUploadTask)

#import "ViewController.h"
//                  ----WebKitFormBoundaryvMI3CAV0sGUtL8tr
#define Kboundary @"----WebKitFormBoundaryjv0UfA04ED44AhWx"

#define KNewLine [@"\r\n" dataUsingEncoding:NSUTF8StringEncoding]

@interface ViewController ()<NSURLSessionDataDelegate>
/** 注释 */
@property (nonatomic, strong) NSURLSession *session;
@end

@implementation ViewController

-(NSURLSession *)session
{
    if (_session == nil) {
        NSURLSessionConfiguration *config = [NSURLSessionConfiguration defaultSessionConfiguration];
        
        //是否运行蜂窝访问
        config.allowsCellularAccess = YES;
        config.timeoutIntervalForRequest = 15;
        
        _session = [NSURLSession sessionWithConfiguration:config delegate:self delegateQueue:[NSOperationQueue mainQueue]];
    }
    return _session;
}

-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
    [self upload2];
}

-(void)upload
{
    //1.url
    NSURL *url = [NSURL URLWithString:@"http://120.25.226.186:32812/upload"];
    
    //2.创建请求对象
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
    
    //2.1 设置请求方法
    request.HTTPMethod = @"POST";

    //2.2 设请求头信息
    [request setValue:[NSString stringWithFormat:@"multipart/form-data; boundary=%@",Kboundary] forHTTPHeaderField:@"Content-Type"];
    
    //3.创建会话对象
//    NSURLSession *session = [NSURLSession sharedSession];
    
    //4.创建上传TASK
    /*
     第一个参数:请求对象
     第二个参数:传递是要上传的数据(请求体)
     第三个参数:
     */
   NSURLSessionUploadTask *uploadTask = [self.session uploadTaskWithRequest:request fromData:[self getBodyData] completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
       
       //6.解析
       NSLog(@"%@",[[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding]);
    }];
    
    //5.执行Task
    [uploadTask resume];
}

-(void)upload2
{
    //1.url
    NSURL *url = [NSURL URLWithString:@"http://120.97.116.186:45632/upload"];
    
    //2.创建请求对象
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
    
    //2.1 设置请求方法
    request.HTTPMethod = @"POST";
    
    //2.2 设请求头信息
    [request setValue:[NSString stringWithFormat:@"multipart/form-data; boundary=%@",Kboundary] forHTTPHeaderField:@"Content-Type"];
    
    //3.创建会话对象
    
    //4.创建上传TASK
    /*
     第一个参数:请求对象
     第二个参数:传递是要上传的数据(请求体)
     */
    NSURLSessionUploadTask *uploadTask = [self.session uploadTaskWithRequest:request fromData:[self getBodyData] completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
        
        //6.解析
        NSLog(@"%@",[[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding]);
    }];
    
    //5.执行Task
    [uploadTask resume];
}

-(NSData *)getBodyData
{
    NSMutableData *fileData = [NSMutableData data];
    //5.1 文件参数
    /*
     --分隔符
     Content-Disposition: form-data; name="file"; filename="Snip20160225_341.png"
     Content-Type: image/png(MIMEType:大类型/小类型)
     空行
     文件参数
     */
    [fileData appendData:[[NSString stringWithFormat:@"--%@",Kboundary] dataUsingEncoding:NSUTF8StringEncoding]];
    [fileData appendData:KNewLine];
    
    //name:file 服务器规定的参数
    //filename:Snip20160225_341.png 文件保存到服务器上面的名称
    //Content-Type:文件的类型
    [fileData appendData:[@"Content-Disposition: form-data; name=\"file\"; filename=\"Sss.png\"" dataUsingEncoding:NSUTF8StringEncoding]];
    [fileData appendData:KNewLine];
    [fileData appendData:[@"Content-Type: image/png" dataUsingEncoding:NSUTF8StringEncoding]];
    [fileData appendData:KNewLine];
    [fileData appendData:KNewLine];
    
    UIImage *image = [UIImage imageNamed:@"Snip20160226_90"];
    //UIImage --->NSData
    NSData *imageData = UIImagePNGRepresentation(image);
    [fileData appendData:imageData];
    [fileData appendData:KNewLine];
    
    //5.2 非文件参数
    /*
     --分隔符
     Content-Disposition: form-data; name="username"
     空行
     123456
     */
    [fileData appendData:[[NSString stringWithFormat:@"--%@",Kboundary] dataUsingEncoding:NSUTF8StringEncoding]];
    [fileData appendData:KNewLine];
    [fileData appendData:[@"Content-Disposition: form-data; name=\"username\"" dataUsingEncoding:NSUTF8StringEncoding]];
    [fileData appendData:KNewLine];
    [fileData appendData:KNewLine];
    [fileData appendData:[@"123456" dataUsingEncoding:NSUTF8StringEncoding]];
    [fileData appendData:KNewLine];
    
    //5.3 结尾标识
    /*
     --分隔符--
     */
    [fileData appendData:[[NSString stringWithFormat:@"--%@--",Kboundary] dataUsingEncoding:NSUTF8StringEncoding]];
    return fileData;
}

#pragma mark ----------------------
#pragma mark NSURLSessionDataDelegate
/*
 *  @param bytesSent                本次发送的数据
 *  @param totalBytesSent           上传完成的数据大小
 *  @param totalBytesExpectedToSend 文件的总大小
 */
-(void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didSendBodyData:(int64_t)bytesSent totalBytesSent:(int64_t)totalBytesSent totalBytesExpectedToSend:(int64_t)totalBytesExpectedToSend
{
    NSLog(@"%f",1.0 *totalBytesSent / totalBytesExpectedToSend);
}
@end

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