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型文件（即> 40MB）到我的应用程序，这个文件将是ZIP或PDF。我使用 NSURLConnection 实现了这一点，如果文件下载一部分填充文件并且执行已停止，则文件较小。例如我试图下载36MB的PDF文件，但是只能下载16MB。请帮我知道原因吗？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?

FYI：
实施文件

FYI: Implementation File

#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 %@' : \n %@ ", 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

标题文件：

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

谢谢，

更新：
这是因为我的可下载文件位于具有下载限制的共享主机中。之后，我把该文件移动到专用服务器，工作正常。而且我也尝试从其他一些网站下载其他文件，如视频，也可以正常工作。
所以，如果你有部分下载的问题，不要只是坚持使用代码，检查服务器太

推荐答案

这是因为我的可下载文件位于具有下载限制的共享主机中。之后，我把该文件移动到专用服务器，工作正常。而且我也试图下载一些其他文件，像其他网站的视频，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.

所以，如果你有部分下载的问题，不要坚持使用代码，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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