IOS文件下载

迷南。 2023-10-18 11:24 13阅读 0赞

<table style="word-wrap:break-word; empty-cells:show; border-collapse:collapse; margin:0px; padding:0px; font-size:14px; border-spacing:0px; table-layout:fixed; width:698px; color:rgb(0,0,0); font-family:宋体; line-height:25px; text-align:start"> 
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  <tr style="word-wrap:break-word; margin:0px; padding:0px"> 
   <td style="word-wrap:break-word; margin:0px; padding:0px; font-size:14px"> <p style="word-wrap:break-word; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px"> <span style="word-wrap:break-word; margin:0px; padding:0px"><a href="http://bbs.189works.com/" style="word-wrap:break-word; color:rgb(0,0,0); text-decoration:initial; margin:0px; padding:0px" rel="nofollow">iOS</a></span>开发中会经常用到文件上传下载的功能，这篇文件将介绍一下如何结合asp.net webservice实现文件上传下载。&nbsp;<br style="word-wrap:break-word"> 首先，让我们看下文件下载。<br style="word-wrap:break-word"> <br style="word-wrap:break-word"> 这里我们下载cnblogs上的一个zip文件。使用NSURLRequest+NSURLConnection可以很方便的实现这个功能。在asp.net webservice中可以将文件的地址返回到iOS系统，iOS系统再通过这个url去请求下载该文件。这里为了简单起见，直接将url写道代码里面了。我们可以使用两种方式去下载文件。<br style="word-wrap:break-word"> <br style="word-wrap:break-word"> 1、同步下载文件：</p> </td> 
  </tr> 
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</table>

NSString *urlAsString = @"http://files.cnblogs.com/zhuqil/UIWebViewDemo.zip"; 
            NSURL    *url = [NSURL URLWithString:urlAsString]; 
            NSURLRequest *request = [NSURLRequest requestWithURL:url]; 
            NSError *error = nil; 
            NSData   *data = http://www.cnblogs.com/zhwl/archive/2012/07/13/[NSURLConnection sendSynchronousRequest:request 
                                                   returningResponse:nil 
                                                               error:&error]; 
            /* 下载的数据 */ 
            if (data != nil){ 
                NSLog(@"下载成功"); 
                if ([data writeToFile:@"UIWebViewDemo.zip" atomically:YES]) { 
                    NSLog(@"保存成功."); 
                } 
                else 
                { 
                    NSLog(@"保存失败."); 
                } 
            } else { 
                NSLog(@"%@", error); 
            }

2.异步下载

DownLoadingViewController.h
    
    //  DownLoadingViewController.h 
    //  DownLoading 
    // 
    //  Created by skylin zhu on 11-7-30. 
    //  Copyright 2011年 mysoft. All rights reserved. 
    // 
    
    #import 
    
    @interface DownLoadingViewController : UIViewController { 
        NSURLConnection *connection;  
        NSMutableData *connectionData; 
    } 
    @property (nonatomic,retain) NSURLConnection *connection;   
    @property (nonatomic,retain) NSMutableData *connectionData; 
    @end 
    
    DownLoadingViewController.m
    
    //  DownLoadingViewController.m 
    //  DownLoading 
    // 
    //  Created by skylin zhu on 11-7-30. 
    //  Copyright 2011年 mysoft. All rights reserved. 
    // 
    
    #import "DownLoadingViewController.h" 
    
    @implementation DownLoadingViewController 
    @synthesize connection,connectionData; 
    - (void)dealloc 
    { 
        [super dealloc]; 
    } 
    
    - (void)didReceiveMemoryWarning 
    { 
        // Releases the view if it doesn't have a superview. 
        [super didReceiveMemoryWarning]; 
        
        // Release any cached data, images, etc that aren't in use. 
    } 
    
    #pragma mark - View lifecycle 
    
    
    // Implement viewDidLoad to do additional setup after loading the view, typically from a nib. 
    - (void)viewDidLoad 
    { 
        [super viewDidLoad]; 
        //文件地址 
        NSString *urlAsString = @"http://files.cnblogs.com/zhuqil/UIWebViewDemo.zip"; 
        NSURL    *url = [NSURL URLWithString:urlAsString]; 
        NSURLRequest *request = [NSURLRequest requestWithURL:url]; 
        NSMutableData *data = http://www.cnblogs.com/zhwl/archive/2012/07/13/[[NSMutableData alloc] init]; 
        self.connectionData = http://www.cnblogs.com/zhwl/archive/2012/07/13/data; 
        [data release]; 
        NSURLConnection *newConnection = [[NSURLConnection alloc] 
                                          initWithRequest:request 
                                          delegate:self 
                                          startImmediately:YES]; 
        self.connection = newConnection; 
        [newConnection release]; 
        if (self.connection != nil){ 
           NSLog(@"Successfully created the connection"); 
        } else { 
            NSLog(@"Could not create the connection"); 
        } 
    } 
    
    
    
    
    - (void) connection:(NSURLConnection *)connection 
                didFailWithError:(NSError *)error{ 
        NSLog(@"An error happened"); 
        NSLog(@"%@", error); 
    } 
    - (void) connection:(NSURLConnection *)connection 
                  didReceiveData:(NSData *)data{ 
        NSLog(@"Received data"); 
        [self.connectionData appendData:data]; 
    } 
    - (void) connectionDidFinishLoading 
    :(NSURLConnection *)connection{ 
        /* 下载的数据 */ 
    
            NSLog(@"下载成功"); 
            if ([self.connectionData writeToFile:@"UIWebViewDemo.zip" atomically:YES]) { 
                NSLog(@"保存成功."); 
            } 
            else 
            { 
                NSLog(@"保存失败."); 
            } 
      
        /* do something with the data here */ 
    } 
    - (void) connection:(NSURLConnection *)connection 
              didReceiveResponse:(NSURLResponse *)response{ 
        [self.connectionData setLength:0]; 
    } 
    
    - (void) viewDidUnload{ 
        [super viewDidUnload]; 
        [self.connection cancel]; 
        self.connection = nil; 
        self.connectionData = http://www.cnblogs.com/zhwl/archive/2012/07/13/nil; 
    } 
    
    @end