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首先自己写个请求数据的类
首先.h文件
#import <Foundation/Foundation.h>
@interface Downloaders : NSObject<NSURLConnectionDataDelegate>
@property (nonatomic, assign) long long beginpt;//下载的起始点
@property (nonatomic, assign) long long endpt;//下载的终点
@property(nonatomic,assign)long long currentLength;//下载的长度
@property(nonatomic,retain)NSString *url;
-(void)starts;
@end
.m文件
#import "Downloaders.h"
#import <Foundation/Foundation.h>
@implementation Downloaders
{
}
-(id)init
{
self = [super init];
if(self)
{
}
return self;
}
-(void)starts
{
[self startDown];
}
-(void)startDown
{
NSURL *urls =[NSURL URLWithString:self.url];
NSMutableURLRequest *request = [[NSMutableURLRequest alloc]initWithURL:urls];
NSString *value = [NSString stringWithFormat:@"bytes=%lld-%lld", self.beginpt + self.currentLength, self.endpt];
[request setValue:value forHTTPHeaderField:@"Range"];
[NSURLConnection connectionWithRequest:request delegate:self];
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
NSString *path = [NSHomeDirectory()stringByAppendingString:@"/Documents"];
NSString *fullpath = [path stringByAppendingPathComponent:@"tests.mp4"];
NSFileManager *fiels= [NSFileManager defaultManager];
if(![fiels fileExistsAtPath:fullpath])
{
[fiels createFileAtPath:fullpath contents:nil attributes:nil];
}
else
{
// NSLog(@"fiel exsits......");
}
NSFileHandle *fielhandel = [NSFileHandle fileHandleForUpdatingAtPath:fullpath];
[ fielhandel seekToFileOffset:self.beginpt + self.currentLength ];
[fielhandel writeData:data];
self.currentLength += data.length;
}
-(void)connectionDidFinishLoading:(NSURLConnection *)connection
{
self.currentLength = 0;
}
然后在需要的地方调用
#import "ViewController.h"
#import "Downloaders.h"
@interface ViewController ()
{
long long totallength;
}
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
[self getfielsize];
long long sizes= 0;
sizes = totallength/4+1;
for(int i=0;i<4;i++)
{
Downloaders *objc = [[Downloaders alloc]init];
objc.url = @"http://172.16.1.92:97/meadia/test.mp4";
objc.beginpt = i*sizes;
objc.endpt = objc.beginpt+sizes-1;
[objc starts];
}
// Do any additional setup after loading the view, typically from a nib.
}
-(void)getfielsize
{
NSString *str = @"http://172.16.1.92:97/meadia/test.mp4";
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:str]];
request.HTTPMethod=@"HEAD";
NSURLResponse *response = nil;
[NSURLConnection sendSynchronousRequest:request returningResponse:&response error:nil];
totallength = response.expectedContentLength;
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
@end
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原文地址：http://www.cnblogs.com/Dr-cyc-blogs/p/4180531.html
