本文轉自:http://www.cnblogs.com/zhuqil/archive/2011/07/30/2122019.html
IOS開發中會經常用到文件上傳下載的功能,這篇文件將介紹一下使用asp.net
webservice實現文件上傳下載。
首先,讓我們看下文件下載。
這裏我們下載cnblogs上的一個zip文件。使用NSURLRequest+NSURLConnection可以很方便的實現這個功能。
同步下載文件:
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];
if (data != nil){
NSLog(@"下載成功");
if ([data writeToFile:@"UIWebViewDemo.zip" atomically:YES]) {
NSLog(@"保存成功.");
}
else
{
NSLog(@"保存失敗.");
}
} else {
NSLog(@"%@", error);
}
異步下載文件:
- (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{
NSLog(@"下載成功");
if ([self.connectionData writeToFile:@"UIWebViewDemo.zip" atomically:YES]) {
NSLog(@"保存成功.");
}
else
{
NSLog(@"保存失敗.");
}
}
- (void) connection:(NSURLConnection *)connection
didReceiveResponse:(NSURLResponse *)response{
[self.connectionData setLength:0];
}
- (void) viewDidUnload{
[super viewDidUnload];
[self.connection cancel];
self.connection = nil;
self.connectionData = nil;
}
從上面兩段代碼中可以看到同步與異步下載的區別,大部分時候我們使用異步下載文件。在asp.net webservice中可以將文件的地址返回到iOS系統,iOS系統在去請求下載該文件。
上傳文件
我們先使用VB.Net寫一個webservice方法,用於接收上傳上來的文件數據,代碼如下。
Public Function UploadFile() As XmlDocument Dim doc As XmlDocument= New XmlDocument() Try Dim postCollection As HttpFileCollection=
Context.Request.Files Dim aFile As HttpPostedFile=
postCollection( "media" ) aFile.SaveAs(Server.MapPath( "." )+ "/" +Path.GetFileName(aFile.FileName)) doc.LoadXml( "ok" ) Return doc Catch ex As Exception doc.LoadXml( "fail" ) Return doc End Try End Function |
文件上傳接口
定義一個類PicOperation用於處理上傳圖片:
@interface
PicOperation : NSOperation { UIImage*theImage; } @property
(retain) UIImage *theImage; @end |
// // PicOperation.m // DownLoading // // Created by skylin zhu on 11-7-30. // Copyright 2011年 mysoft. All rights reserved. // #import "PicOperation.h" #define NOTIFY_AND_LEAVE(X) {[self cleanup:X]; return;} #define DATA(X) [X dataUsingEncoding:NSUTF8StringEncoding] // Posting constants #define IMAGE_CONTENT @"Content-Disposition: form-data; name="%@"; filename="image.jpg"\r\nContent-Type: image/jpeg\r\n\r\n" #define STRING_CONTENT @"Content-Disposition: form-data; name="%@"\r\n\r\n" #define MULTIPART @"multipart/form-data; boundary=------------0x0x0x0x0x0x0x0x" @implementation PicOperation @synthesize theImage; //創建postdata - (NSData*)generateFormDataFromPostDictionary:(NSDictionary*)dict { id boundary = @"------------0x0x0x0x0x0x0x0x"; NSArray* keys = [dict allKeys]; NSMutableData* result = [NSMutableData data]; for (int i = 0; i < [keys count]; i++) { id value = [dict valueForKey: [keys objectAtIndex:i]]; [result appendData:[[NSString stringWithFormat:@"--%@\r\n", boundary] dataUsingEncoding:NSUTF8StringEncoding]]; if ([value isKindOfClass:[NSData class]]) { // handle image data NSString *formstring = [NSString stringWithFormat:IMAGE_CONTENT, [keys objectAtIndex:i]]; [result appendData: DATA(formstring)]; [result appendData:value]; } else { // all non-image fields assumed to be strings NSString *formstring = [NSString stringWithFormat:STRING_CONTENT, [keys objectAtIndex:i]]; [result appendData: DATA(formstring)]; [result appendData:DATA(value)]; } NSString *formstring = @"\r\n"; [result appendData:DATA(formstring)]; } NSString *formstring =[NSString stringWithFormat:@"--%@--\r\n", boundary]; [result appendData:DATA(formstring)]; return result; } //上傳圖片 - (NSString *) UpLoading { if (!self.theImage) NOTIFY_AND_LEAVE(@"Please set image before uploading."); NSMutableDictionary* post_dict = [[NSMutableDictionary alloc] init]; [post_dict setObject:@"Posted from iPhone" forKey:@"message"]; [post_dict setObject:UIImageJPEGRepresentation(self.theImage, 0.75f) forKey:@"media"]; NSData *postData = [self generateFormDataFromPostDictionary:post_dict]; [post_dict release]; NSString *baseurl = @"http://10.5.23.121:7878/WorkflowService.asmx/UploadFile"; NSURL *url = [NSURL URLWithString:baseurl]; NSMutableURLRequest *urlRequest = [NSMutableURLRequest requestWithURL:url]; if (!urlRequest) NOTIFY_AND_LEAVE(@"Error creating the URL Request"); [urlRequest setHTTPMethod: @"POST"]; [urlRequest setValue:MULTIPART forHTTPHeaderField: @"Content-Type"]; [urlRequest setHTTPBody:postData]; // Submit & retrieve results NSError *error; NSURLResponse *response; NSLog(@"Contacting TwitPic...."); NSData* result = [NSURLConnection sendSynchronousRequest:urlRequest returningResponse:&response error:&error]; if (!result) { [self cleanup:[NSString stringWithFormat:@"Submission error: %@", [error localizedDescription]]]; return; } // Return results NSString *outstring = [[[NSString alloc] initWithData:result encoding:NSUTF8StringEncoding] autorelease]; return outstring; } @end
這裏我主要定義了兩個方法,一個是generateFormDataFromPostDictionary用於創建post form data,一個是UpLoading供調用的類上傳圖片,這個類需要一個UIimage的對象。
類定義好了,上傳圖片就非常方便了,看下面代碼:
PicOperation *pic = [[PicOperation alloc] init]; pic.theImage=[UIImage imageNamed:@"meinv4.jpg"];; NSString *result = [pic UpLoading]; NSLog(result);
總結:這篇文章講述瞭如何在iOS中結合asp.net webservice實現文件的上傳和下載功能。