NSURLConnection 下载大文件 (>40MB) [英] NSURLConnection download large file (>40MB)

问题描述

我需要从服务器下载大文件(即 > 40MB)到我的应用程序，该文件将是 ZIP 或 PDF.我使用 NSURLConnection 实现了它，如果文件较小，则效果很好，否则它会下载一部分填充物并且执行已停止.例如我试图下载 36MB 的 PDF 文件，但只下载了 16MB.请帮我知道原因?如何解决?

I need to download large file (i.e. > 40MB) to my application from server, this file will be ZIP or PDF. I achieved it using NSURLConnection, that works well if the file is smaller other wise it download a part of the fill and the execution has stopped. for example I tried to download 36MB PDF file, but but 16MB only downloaded. pls help me to know the reason? how to fix it?

仅供参考:实施文件

#import "ZipHandlerV1ViewController.h"
@implementation ZipHandlerV1ViewController
- (void)dealloc
{
    [super dealloc];
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
}
 - (void)viewDidLoad
 {
     UIView *mainView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 400, 400)];
     [mainView setBackgroundColor:[UIColor darkGrayColor]];

     UIButton *downloadButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
     [downloadButton setFrame:CGRectMake(50, 50, 150, 50)];
     [downloadButton setTitle:@"Download File" forState:UIControlStateNormal];
     [downloadButton addTarget:self action:@selector(downloadFileFromURL:) forControlEvents:UIControlEventTouchUpInside];
     [mainView addSubview:downloadButton];

     [self setRequestURL:@"http://www.mobileveda.com/r_d/mcps/optimized_av_allpdf.pdf"];
     [self.view addSubview:mainView];

     [super viewDidLoad];
 }

- (void)viewDidUnload
{
    [super viewDidUnload];
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}


-(void) setRequestURL:(NSString*) requestURL {
    url = requestURL;
}

-(void) downloadFileFromURL:(id) sender {
    NSURL *reqURL =  [NSURL URLWithString:url];

    NSMutableURLRequest *theRequest = [NSMutableURLRequest requestWithURL:reqURL];
    NSURLConnection *theConnection = [[NSURLConnection alloc] initWithRequest:theRequest delegate:self];
    if (theConnection) {
       webData = [[NSMutableData data] retain];
    } else {
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Error !" message:@"Error has occured, please verify internet connection"  delegate:nil cancelButtonTitle:@"Ok" otherButtonTitles:nil];

        [alert show];
        [alert release];
    }
}

-(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
    [webData setLength:0]; 
}

-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
    [webData appendData:data];
}

-(void)connectionDidFinishLoading:(NSURLConnection *)connection {
   NSString *fileName = [[[NSURL URLWithString:url] path] lastPathComponent];
    NSArray *pathArr = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *folder = [pathArr objectAtIndex:0];

    NSString *filePath = [folder stringByAppendingPathComponent:fileName];
    NSURL *fileURL = [NSURL fileURLWithPath:filePath];
    NSError *writeError = nil;

    [webData writeToURL: fileURL options:0 error:&writeError];
    if( writeError) {
        NSLog(@" Error in writing file %@' : 
 %@ ", filePath , writeError );
        return;
    }
    NSLog(@"%@",fileURL);
}

-(void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Error !" message:@"Error has occured, please verify internet connection.."  delegate:nil cancelButtonTitle:@"Ok" otherButtonTitles:nil];

    [alert show];
    [alert release];

}

@end

头文件:

#import <UIKit/UIKit.h>
@interface ZipHandlerV1ViewController : UIViewController {
    NSMutableData *webData;
    NSString *url;
}
-(void) setRequestURL:(NSString*) requestURL;
@end

谢谢，

更新:发生这种情况是因为我的可下载文件位于共享主机中，有下载限制.在我将该文件移动到工作正常的专用服务器之后.而且我还尝试从其他一些网站下载一些其他文件，如视频，这也工作正常.所以，如果遇到部分下载等问题，不要只看代码，还要检查服务器

推荐答案

发生这种情况是因为我的可下载文件位于共享主机中，有下载限制.在我将该文件移动到工作正常的专用服务器之后.并且我还尝试从其他一些网站下载一些其他文件，如视频，也可以正常工作.

This happens because of my downloadable file was in shared hosting which having the download limitations. After I moved that file to dedicated server that working fine. and also I tried to download some other files like videos from some other sites, that also working fine.

因此，如果您遇到部分下载等问题，请不要只坚持代码，还要检查服务器.

So, if you having problem like partial download, don't only stick with the code, check the server too.

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