iOS-网络-NSURLConnection实现文件下载

一.一般方法
// ViewController.m

#import "ViewController.h"

@interface ViewController ()<NSURLConnectionDataDelegate>
/** 注释 */
@property (nonatomic, strong) NSMutableData *fileData;
@property (nonatomic, assign) NSInteger totalSize;
@property (weak, nonatomic) IBOutlet UIImageView *imageView;
@end

@implementation ViewController

-(NSMutableData *)fileData
{
if (_fileData == nil) {
_fileData = [NSMutableData data];
}
return _fileData;
}
-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
[self download3];
}

//耗时操作[NSData dataWithContentsOfURL:url]
-(void)download1
{
//1.url
NSURL *url = [NSURL URLWithString:@"http://img5.imgtn.bdimg.com/it/u=1915764121,2488815998&fm=21&gp=0.jpg"];

//2.下载二进制数据
NSData *data = [NSData dataWithContentsOfURL:url];

//3.转换
UIImage *image = [UIImage imageWithData:data];
}

//1.无法监听进度
//2.内存飙升
-(void)download2
{
//1.url
// NSURL *url = [NSURL URLWithString:@"http://imgsrc.baidu.com/forum/w%3D580/sign=54a8cc6f728b4710ce2ffdc4f3cec3b2/d143ad4bd11373f06c0b5bd1a40f4bfbfbed0443.jpg"];

NSURL *url = [NSURL URLWithString:@"http://120.25.226.186:32812/resources/videos/minion_01.mp4"];

//2.创建请求对象
NSURLRequest *request = [NSURLRequest requestWithURL:url];

//3.发送请求
[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse * _Nullable response, NSData * _Nullable data, NSError * _Nullable connectionError) {

//4.转换
// UIImage *image = [UIImage imageWithData:data];
//
// self.imageView.image = image;
//NSLog(@"%@",connectionError);

//4.写数据到沙盒中
NSString *fullPath = [[NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject]stringByAppendingPathComponent:@"123.mp4"];
[data writeToFile:fullPath atomically:YES];
}];
}

//内存飙升
-(void)download3
{
//1.url
// NSURL *url = [NSURL URLWithString:@"http://imgsrc.baidu.com/forum/w%3D580/sign=54a8cc6f728b4710ce2ffdc4f3cec3b2/d143ad4bd11373f06c0b5bd1a40f4bfbfbed0443.jpg"];

NSURL *url = [NSURL URLWithString:@"http://120.25.226.186:32812/resources/videos/minion_01.mp4"];

//2.创建请求对象
NSURLRequest *request = [NSURLRequest requestWithURL:url];

//3.发送请求
[[NSURLConnection alloc]initWithRequest:request delegate:self];
}

#pragma mark ----------------------
#pragma mark NSURLConnectionDataDelegate
-(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
NSLog(@"didReceiveResponse");

//得到文件的总大小(本次请求的文件数据的总大小)
self.totalSize = response.expectedContentLength;
}

-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
// NSLog(@"%zd",data.length);
[self.fileData appendData:data];

//进度=已经下载/文件的总大小
NSLog(@"%f",1.0 * self.fileData.length /self.totalSize);
}
-(void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
}

-(void)connectionDidFinishLoading:(NSURLConnection *)connection
{
NSLog(@"connectionDidFinishLoading");
//4.写数据到沙盒中
NSString *fullPath = [[NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject]stringByAppendingPathComponent:@"123.mp4"];

[self.fileData writeToFile:fullPath atomically:YES];
NSLog(@"%@",fullPath);
}
@end


二.大文件断点下载,NSFileHandle,NSOutputStream

//  ViewController.m
//  08-掌握-小文件下载

#import "ViewController.h"

@interface ViewController ()<NSURLConnectionDataDelegate>
@property (weak, nonatomic) IBOutlet UIProgressView *progressView;

@property (nonatomic, assign) NSInteger totalSize;
@property (nonatomic, assign) NSInteger currentSize;
/** 沙盒路径 */
@property (nonatomic, strong) NSString *fullPath;
/** 连接对象 */
@property (nonatomic, strong) NSURLConnection *connect;
/** 输出流*/
@property (nonatomic, strong) NSOutputStream *stream;
/** 文件句柄*/
//@property (nonatomic, strong)NSFileHandle *handle;

@end

@implementation ViewController

- (IBAction)startBtnClick:(id)sender {
[self download];
}
- (IBAction)cancelBtnClick:(id)sender {
[self.connect cancel];
}
- (IBAction)goOnBtnClick:(id)sender {
[self download];
}

//内存飙升
-(void)download
{
//1.url
// NSURL *url = [NSURL URLWithString:@"http://imgsrc.baidu.com/forum/w%3D580/sign=54a8cc6f728b4710ce2ffdc4f3cec3b2/d143ad4bd11373f06c0b5bd1a40f4bfbfbed0443.jpg"];

NSURL *url = [NSURL URLWithString:@"http://www.33lc.com/article/UploadPic/2012-10/2012102514201759594.jpg"];

//2.创建请求对象
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];

//设置请求头信息,告诉服务器值请求一部分数据range
/*
bytes=0-100
bytes=-100
bytes=0- 请求100之后的所有数据
*/
NSString *range = [NSString stringWithFormat:@"bytes=%zd-",self.currentSize];
[request setValue:range forHTTPHeaderField:@"Range"];
NSLog(@"+++++++%@",range);

//3.发送请求
NSURLConnection *connect = [[NSURLConnection alloc]initWithRequest:request delegate:self];
self.connect = connect;
}

#pragma mark ----------------------
#pragma mark NSURLConnectionDataDelegate
-(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
NSLog(@"didReceiveResponse");

//1.得到文件的总大小(本次请求的文件数据的总大小 != 文件的总大小)
// self.totalSize = response.expectedContentLength + self.currentSize;

if (self.currentSize >0) {
return;
}

self.totalSize = response.expectedContentLength;

//2.写数据到沙盒中
self.fullPath = [[NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject]stringByAppendingPathComponent:@"123.jpg"];

NSLog(@"%@",self.fullPath);
//3.创建输出流
//    NSOutputStream
//    NSInputStream
/*
第一个参数:文件的路径
第二个参数:YES 追加
特点:如果该输出流指向的地址没有文件,那么会自动创建一个空的文件
*/
NSOutputStream *stream = [[NSOutputStream alloc]initToFileAtPath:self.fullPath append:YES];

//打开输出流
[stream open];
self.stream = stream;

//    //使用文件句柄
//    //3.创建一个空的文件
//    [[NSFileManager defaultManager] createFileAtPath:self.fullPath contents:nil attributes:nil];
//    //4.创建文件句柄(指针)
//    self.handle = [NSFileHandle fileHandleForWritingAtPath:self.fullPath];
//

}

-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
//写数据
[self.stream write:data.bytes maxLength:data.length];

//    //1.移动文件句柄到数据的末尾
//    [self.handle seekToEndOfFile];
//    //2.写数据
//    [self.handle writeData:data];

//3.获得进度
self.currentSize += data.length;

//进度=已经下载/文件的总大小
NSLog(@"%f",1.0 *  self.currentSize/self.totalSize);
self.progressView.progress = 1.0 *  self.currentSize/self.totalSize;
//NSLog(@"%@",self.fullPath);
}

-(void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
}

-(void)connectionDidFinishLoading:(NSURLConnection *)connection
{

//关闭流
[self.stream close];
self.stream = nil;
//    //1.关闭文件句柄
//    [self.handle closeFile];
//    self.handle = nil;

NSLog(@"connectionDidFinishLoading");
NSLog(@"%@",self.fullPath);
}
@end