【网络】iOS上传下载

﹏ヽ暗。殇╰゛Y 2022-08-20 09:17 177阅读 0赞

首先，让我们看下文件下载。

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。

同步下载文件：

[![复制代码][copycode.gif]][copycode.gif 1]

NSString *urlAsString = @"http://files.cnblogs.com/zhuqil/UIWebViewDemo.zip";
            NSURL    *url = [NSURL URLWithString:urlAsString];
            NSURLRequest *request = [NSURLRequest requestWithURL:url];
            NSError *error = nil;
            NSData   *data = [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);
            }

[![复制代码][copycode.gif]][copycode.gif 1]

异步下载文件：

[![复制代码][copycode.gif]][copycode.gif 1]

- (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 = [[NSMutableData alloc] init];
        self.connectionData = 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 = nil;
    }

[![复制代码][copycode.gif]][copycode.gif 1]

从上面两段代码中可以看到同步与异步下载的区别，大部分时候我们使用异步下载文件。在asp.net webservice中可以将文件的地址返回到iOS系统，iOS系统在去请求下载该文件。

上传文件

文件上传接口

定义一个类PicOperation用于处理上传图片：

[?][Link 1]

<table> 
 <tbody style="margin:0px!important; padding:0px!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:2em!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-family:'Courier New',Consolas,'Bitstream Vera Sans Mono',Courier,monospace!important; font-size:12px!important; min-height:inherit!important"> 
  <tr style="margin:0px!important; padding:0px!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:2em!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; min-height:inherit!important"> 
   <td style="padding:3px; border:1px; width:921px; border-collapse:collapse; margin:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:2em!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; font-family:'Courier New',Consolas,'Bitstream Vera Sans Mono',Courier,monospace!important; min-height:inherit!important"> 
    <div style="margin:0px!important; padding:0px!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:2em!important; outline:0px!important; overflow:visible!important; position:relative!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; min-height:inherit!important"> 
     <div style="margin:0px!important; padding:0px 5px!important; background-color:rgb(248,248,248)!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:2em!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; min-height:inherit!important; white-space:pre!important"> 
      <code style="white-space:pre-wrap; margin:0px!important; padding:0px!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:2em!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-family:'Courier New',Consolas,'Bitstream Vera Sans Mono',Courier,monospace!important; min-height:inherit!important">@interface PicOperation : NSOperation </code> 
     </div> 
     <div style="margin:0px!important; padding:0px 5px!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:2em!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; min-height:inherit!important; white-space:pre!important"> 
      <code style="white-space:pre-wrap; margin:0px!important; padding:0px!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:2em!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-family:'Courier New',Consolas,'Bitstream Vera Sans Mono',Courier,monospace!important; min-height:inherit!important">{ </code> 
     </div> 
     <div style="margin:0px!important; padding:0px 5px!important; background-color:rgb(248,248,248)!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:2em!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; min-height:inherit!important; white-space:pre!important"> 
      <code style="white-space:pre-wrap; margin:0px!important; padding:0px!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:2em!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-family:'Courier New',Consolas,'Bitstream Vera Sans Mono',Courier,monospace!important; min-height:inherit!important">&nbsp;&nbsp;&nbsp;&nbsp;</code> 
      <code style="white-space:pre-wrap; margin:0px!important; padding:0px!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:2em!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-family:'Courier New',Consolas,'Bitstream Vera Sans Mono',Courier,monospace!important; min-height:inherit!important">UIImage *theImage;</code> 
     </div> 
     <div style="margin:0px!important; padding:0px 5px!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:2em!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; min-height:inherit!important; white-space:pre!important"> 
      <code style="white-space:pre-wrap; margin:0px!important; padding:0px!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:2em!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-family:'Courier New',Consolas,'Bitstream Vera Sans Mono',Courier,monospace!important; min-height:inherit!important">}</code> 
     </div> 
     <div style="margin:0px!important; padding:0px 5px!important; background-color:rgb(248,248,248)!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:2em!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; min-height:inherit!important; white-space:pre!important"> 
      <code style="white-space:pre-wrap; margin:0px!important; padding:0px!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:2em!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-family:'Courier New',Consolas,'Bitstream Vera Sans Mono',Courier,monospace!important; min-height:inherit!important">@property (retain) UIImage *theImage;</code> 
     </div> 
     <div style="margin:0px!important; padding:0px 5px!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:2em!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; min-height:inherit!important; white-space:pre!important"> 
      <code style="white-space:pre-wrap; margin:0px!important; padding:0px!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:2em!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-family:'Courier New',Consolas,'Bitstream Vera Sans Mono',Courier,monospace!important; min-height:inherit!important">@end</code> 
     </div> 
    </div> </td> 
  </tr> 
 </tbody> 
</table>

**\[objc\]**  [view plain][]  [copy][view plain]

1.  //  
2.  //  PicOperation.m  
3.  //  DownLoading  
4.  //  
5.  //  Created by skylin zhu on 11-7-30.  
6.  //  Copyright 2011年 mysoft. All rights reserved.  
7.  //  
8.    
9.  \#import "PicOperation.h"  
10.   
11. \#define NOTIFY\_AND\_LEAVE(X) \{\[self cleanup:X\]; return;\}  
12. \#define DATA(X) \[X dataUsingEncoding:NSUTF8StringEncoding\]  
13.   
14. // Posting constants  
15. \#define IMAGE\_CONTENT @"Content-Disposition: form-data; name=\\"%@\\"; filename=\\"image.jpg\\"\\r\\nContent-Type: image/jpeg\\r\\n\\r\\n"  
16. \#define STRING\_CONTENT @"Content-Disposition: form-data; name=\\"%@\\"\\r\\n\\r\\n"  
17. \#define MULTIPART @"multipart/form-data; boundary=------------0x0x0x0x0x0x0x0x"  
18.   
19. **@implementation** PicOperation  
20. **@synthesize** theImage;  
21.   
22. //创建postdata  
23. \- (NSData\*)generateFormDataFromPostDictionary:(NSDictionary\*)dict  
24. \{  
25.     **id** boundary = @"------------0x0x0x0x0x0x0x0x";  
26.     NSArray\* keys = \[dict allKeys\];  
27.     NSMutableData\* result = \[NSMutableData data\];  
28.       
29.     **for** (**int** i = 0; i < \[keys count\]; i++)   
30.     \{  
31.         **id** value = \[dict valueForKey: \[keys objectAtIndex:i\]\];  
32.         \[result appendData:\[\[NSString stringWithFormat:@"--%@\\r\\n", boundary\] dataUsingEncoding:NSUTF8StringEncoding\]\];  
33.           
34.         **if** (\[value isKindOfClass:\[NSData class\]\])   
35.         \{  
36.             // handle image data  
37.             **NSString** \*formstring = \[NSString stringWithFormat:IMAGE\_CONTENT, \[keys objectAtIndex:i\]\];  
38.             \[result appendData: DATA(formstring)\];  
39.             \[result appendData:value\];  
40.         \}  
41.         **else**   
42.         \{  
43.             // all non-image fields assumed to be strings  
44.             **NSString** \*formstring = \[NSString stringWithFormat:STRING\_CONTENT, \[keys objectAtIndex:i\]\];  
45.             \[result appendData: DATA(formstring)\];  
46.             \[result appendData:DATA(value)\];  
47.         \}  
48.           
49.         **NSString** \*formstring = @"\\r\\n";  
50.         \[result appendData:DATA(formstring)\];  
51.     \}  
52.       
53.     **NSString** \*formstring =\[NSString stringWithFormat:@"--%@--\\r\\n", boundary\];  
54.     \[result appendData:DATA(formstring)\];  
55.     **return** result;  
56. \}  
57. //上传图片  
58. \- (**NSString** \*) UpLoading  
59. \{  
60.     **if** (!**self**.theImage)  
61.         NOTIFY\_AND\_LEAVE(@"Please set image before uploading.");  
62.       
63.       
64.     NSMutableDictionary\* post\_dict = \[\[NSMutableDictionary alloc\] init\];  
65.       
66.     \[post\_dict setObject:@"Posted from iPhone" forKey:@"message"\];  
67.     \[post\_dict setObject:UIImageJPEGRepresentation(**self**.theImage, 0.75f) forKey:@"media"\];  
68.       
69.     **NSData** \*postData = \[**self** generateFormDataFromPostDictionary:post\_dict\];  
70.     \[post\_dict release\];  
71.       
72.     **NSString** \*baseurl = @"http://10.5.23.121:7878/WorkflowService.asmx/UploadFile";   
73.     **NSURL** \*url = \[NSURL URLWithString:baseurl\];  
74.     **NSMutableURLRequest** \*urlRequest = \[NSMutableURLRequest requestWithURL:url\];  
75.     **if** (!urlRequest) NOTIFY\_AND\_LEAVE(@"Error creating the URL Request");  
76.       
77.     \[urlRequest setHTTPMethod: @"POST"\];  
78.     \[urlRequest setValue:MULTIPART forHTTPHeaderField: @"Content-Type"\];  
79.     \[urlRequest setHTTPBody:postData\];  
80.       
81.     // Submit & retrieve results  
82.     **NSError** \*error;  
83.     **NSURLResponse** \*response;  
84.     NSLog(@"Contacting TwitPic....");  
85.     NSData\* result = \[NSURLConnection sendSynchronousRequest:urlRequest returningResponse:&response error:&error\];  
86.     **if** (!result)  
87.     \{  
88.         \[**self** cleanup:\[NSString stringWithFormat:@"Submission error: %@", \[error localizedDescription\]\]\];  
89.         **return**;  
90.     \}  
91.       
92.     // Return results  
93.     **NSString** \*outstring = \[\[\[NSString alloc\] initWithData:result encoding:NSUTF8StringEncoding\] autorelease\];  
94.     **return** outstring;  
95. \}  
96. **@end**

这里我主要定义了两个方法，一个是generateFormDataFromPostDictionary用于创建post form data，一个是UpLoading供调用的类上传图片，这个类需要一个UIimage的对象。

类定义好了，上传图片就非常方便了，看下面代码：

**\[objc\]**  [view plain][]  [copy][view plain]

1.  **PicOperation** \*pic = \[\[PicOperation alloc\] init\];  
2.  pic.theImage=\[UIImage imageNamed:@"meinv4.jpg"\];;  
3.  **NSString** \*result = \[pic UpLoading\];  
4.  NSLog(result);

总结：这篇文章讲述了如何在iOS中结合asp.net webservice实现文件的上传和下载功能。

顶

[copycode.gif]: http://common.cnblogs.com/images/copycode.gif
[copycode.gif 1]: /images/20220731/23ec19163f24445c9c7edd816f2f0a4f.png
[Link 1]: /images/20220731/23ec19163f24445c9c7edd816f2f0a4f.png#
[view plain]: http://blog.csdn.net/ch_soft/article/details/7661539#