ios 文件上传， post数据

2019-11-07 23:14:10

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ios 文件上传， post数据

2014-07-22 16:44 43110人阅读评论(2) 收藏举报

分类：ios（19）

一、文件下载

获取资源文件大小有两张方式

1、

[objc] view plain copy

HTTP HEAD方法 NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url cachePolicy:0 timeoutInterval:kTimeout]; request.HTTPMethod = @"HEAD"; [NSURLConnection sendAsynchronousRequest:request queue:self.myQueue completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) { NSLog(@"%@", response); NSLog(@"---------------"); NSLog(@"%@", data); }]; 运行测试代码可以发现，HEAD方法只是返回资源信息，而不会返回数据体应用场景：获取资源Mimetype 获取资源文件大小，用于端点续传或多线程下载 2

[objc] view%20plain copy

使用块代码获取网络资源大小的方法 - (void)fileSizeWithURL:(NSURL *)url completion:(void (^)(long long contentLength))completion { NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url cachePolicy:0 timeoutInterval:kTimeout]; request.HTTPMethod = @"HEAD"; NSURLResponse *response = nil; [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:NULL]; completion(response.expectedContentLength); } 确定每次下载数据包的伪代码实现

[objc] view%20plain copy

- (void)downloadFileWithURL:(NSURL *)url { [self fileSizeWithURL:url completion:^(long long contentLength) { NSLog(@"文件总大小：%lld", contentLength); // 根据大小下载文件 while (contentLength > kDownloadBytes) { NSLog(@"每次下载长度：%lld", (long long)kDownloadBytes); contentLength -= kDownloadBytes; } NSLog(@"最后下载字节数：%lld", contentLength); }]; } HTTP%20Range的示例通过设置Range可以指定每次从网路下载数据包的大小Range示例bytes=0-499%20从0到499的头500个字节bytes=500-999%20从500到999的第二个500字节bytes=500-%20从500字节以后的所有字节bytes=-500%20最后500个字节bytes=500-599,800-899%20同时指定几个范围Range小结-%20用于分隔前面的数字表示起始字节数后面的数组表示截止字节数，没有表示到末尾,%20用于分组，可以一次指定多个Range，不过很少用

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分段Range代码实现 long long fromBytes = 0; long long toBytes = 0; while (contentLength > kDownloadBytes) { toBytes = fromBytes + kDownloadBytes - 1; NSString *range = [NSString stringWithFormat:@"bytes=%lld-%lld", fromBytes, toBytes]; NSLog(@"range %@", range); fromBytes += kDownloadBytes; contentLength -= kDownloadBytes; } fromBytes = fromBytes + contentLength - 1; NSString *range = [NSString stringWithFormat:@"bytes=%lld-%lld", fromBytes, toBytes]; NSLog(@"range %@", range); [objc] view%20plain copy

分段下载文件 NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url cachePolicy:NSURLRequestReloadIgnoringCacheData timeoutInterval:kTimeout]; NSString *range = [NSString stringWithFormat:@"bytes=%lld-%lld", from, end]; [request setValue:range forHTTPHeaderField:@"Range"]; NSURLResponse *response = nil; NSData *data = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:NULL]; NSLog(@"%@-%@-%ld", range, response, (unsigned long)data.length); 提示：如果GET包含Range请求头，响应会以状态码206（PartialContent）返回而不是200（OK） [objc] view%20plain copy

将数据写入文件 // 打开缓存文件 NSFileHandle *fp = [NSFileHandle fileHandleForWritingAtPath:self.cachePath]; // 如果文件不存在，直接写入数据 if (!fp) { [data writeToFile:self.cachePath atomically:YES]; } else { // 移动到文件末尾 [fp seekToEndOfFile]; // 将数据文件追加到文件末尾 [fp writeData:data]; // 关闭文件句柄 [fp closeFile]; } [objc] view%20plain copy

检查文件大小 // 判断文件是否存在 if ([[NSFileManager defaultManager] fileExistsAtPath:self.cachePath]) { NSDictionary *dict = [[NSFileManager defaultManager] attributesOfItemAtPath:self.cachePath error:NULL]; return [dict[NSFileSize] longLongValue]; } else { return 0; } 提示：由于数据是追加的，为了避免重复从网络下载文件，在下载之前判断缓存路径中文件是否已经存在如果存在检查文件大小如果文件大小与网络资源大小一致，则不再下载全部代码如下

[objc] view%20plain copy

// // MJViewController.m // 01.文件下载 // // Created by apple on 14-4-29. // Copyright (c) 2014年 itcast. All rights reserved. // #import "MJViewController.h" #import "FileDownload.h" @interface MJViewController () @PRoperty (nonatomic, strong) FileDownload *download; @property (weak, nonatomic) IBOutlet UIImageView *imageView; @end @implementation MJViewController - (void)viewDidLoad { [super viewDidLoad]; self.download = [[FileDownload alloc] init]; [self.download downloadFileWithURL:[NSURL URLWithString:@"http://localhost/itcast/images/head4.png"] completion:^(UIImage *image) { self.imageView.image = image; }]; } @end [objc] view plain copy

// // FileDownload.m // 01.文件下载 // // Created by apple on 14-4-29. // Copyright (c) 2014年 itcast. All rights reserved. // #import "FileDownload.h" #import "NSString+PassWord.h" #define kTimeOut 2.0f // 每次下载的字节数 #define kBytesPerTimes 20250 @interface FileDownload() @property (nonatomic, strong) NSString *cacheFile; @property (nonatomic, strong) UIImage *cacheImage; @end @implementation FileDownload /** 为了保证开发的简单,所有方法都不使用多线程,所有的注意力都保持在文件下载上在开发中如果碰到比较绕的计算问题时,建议: 1> 测试数据不要太大 2> 测试数据的数值变化,能够用笔算计算出准确的数值 3> 编写代码对照测试 */ //- (NSString *)cacheFile //{ // if (!_cacheFile) { // NSString *cacheDir = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES)[0]; // _cacheFile = [cacheDir stringByAppendingPathComponent:@"123.png"]; // } // return _cacheFile; //} - (UIImage *)cacheImage { if (!_cacheImage) { _cacheImage = [UIImage imageWithContentsOfFile:self.cacheFile]; } return _cacheImage; } - (void)setCacheFile:(NSString *)urlStr { NSString *cacheDir = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES)[0]; urlStr = [urlStr md5]; _cacheFile = [cacheDir stringByAppendingPathComponent:urlStr]; } - (void)downloadFileWithURL:(NSURL *)url completion:(void (^)(UIImage *image))completion { // GCD中的串行队列异步方法 dispatch_queue_t q = dispatch_queue_create("cn.itcast.download", DISPATCH_QUEUE_SERIAL); dispatch_async(q, ^{ NSLog(@"%@", [NSThread currentThread]); // 把对URL进行MD5加密之后的结果当成文件名 self.cacheFile = [url absoluteString]; // 1. 从网络下载文件,需要知道这个文件的大小 long long fileSize = [self fileSizeWithURL:url]; // 计算本地缓存文件大小 long long cacheFileSize = [self localFileSize]; if (cacheFileSize == fileSize) { dispatch_async(dispatch_get_main_queue(), ^{ completion(self.cacheImage); }); NSLog(@"文件已经存在"); return; } // 2. 确定每个数据包的大小 long long fromB = 0; long long toB = 0; // 计算起始和结束的字节数 while (fileSize > kBytesPerTimes) { // 20480 + 20480 // toB = fromB + kBytesPerTimes - 1; // 3. 分段下载文件 [self downloadDataWithURL:url fromB:fromB toB:toB]; fileSize -= kBytesPerTimes; fromB += kBytesPerTimes; } [self downloadDataWithURL:url fromB:fromB toB:fromB + fileSize - 1]; dispatch_async(dispatch_get_main_queue(), ^{ completion(self.cacheImage); }); }); } #pragma mark 下载指定字节范围的数据包 /** NSURLRequestUseProtocolCachePolicy = 0, // 默认的缓存策略,内存缓存 NSURLRequestReloadIgnoringLocalCacheData = 1, // 忽略本地的内存缓存 NSURLRequestReloadIgnoringCacheData */ - (void)downloadDataWithURL:(NSURL *)url fromB:(long long)fromB toB:(long long)toB { NSLog(@"数据包:%@", [NSThread currentThread]); NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url cachePolicy:NSURLRequestReloadIgnoringCacheData timeoutInterval:kTimeOut]; // 指定请求中所要GET的字节范围 NSString *range = [NSString stringWithFormat:@"Bytes=%lld-%lld", fromB, toB]; [request setValue:range forHTTPHeaderField:@"Range"]; NSLog(@"%@", range); NSURLResponse *response = nil; NSData *data = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:NULL]; // 写入文件,覆盖文件不会追加 // [data writeToFile:@"/Users/aplle/Desktop/1.png" atomically:YES]; [self appendData:data]; NSLog(@"%@", response); } #pragma mark - 读取本地缓存文件大小 - (long long)localFileSize { // 读取本地文件信息 NSDictionary *dict = [[NSFileManager defaultManager] attributesOfItemAtPath:self.cacheFile error:NULL]; NSLog(@"%lld", [dict[NSFileSize] longLongValue]); return [dict[NSFileSize] longLongValue]; } #pragma mark - 追加数据到文件 - (void)appendData:(NSData *)data { // 判断文件是否存在 NSFileHandle *fp = [NSFileHandle fileHandleForWritingAtPath:self.cacheFile]; // 如果文件不存在创建文件 if (!fp) { [data writeToFile:self.cacheFile atomically:YES]; } else { // 如果文件已经存在追加文件 // 1> 移动到文件末尾 [fp seekToEndOfFile]; // 2> 追加数据 [fp writeData:data]; // 3> 写入文件 [fp closeFile]; } } #pragma mark - 获取网络文件大小 - (long long)fileSizeWithURL:(NSURL *)url { // 默认是GET NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url cachePolicy:0 timeoutInterval:kTimeOut]; // HEAD 头,只是返回文件资源的信息,不返回具体是数据 // 如果要获取资源的MIMEType,也必须用HEAD,否则,数据会被重复下载两次 request.HTTPMethod = @"HEAD"; // 使用同步方法获取文件大小 NSURLResponse *response = nil; [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:NULL]; // expectedContentLength文件在网络上的大小 NSLog(@"%lld", response.expectedContentLength); return response.expectedContentLength; } @end

二、文件上传

代码如下

[objc] view plain copy

// // MJViewController.m // 02.Post上传 // // Created by apple on 14-4-29. // Copyright (c) 2014年 itcast. All rights reserved. // #import "MJViewController.h" #import "UploadFile.h" @interface MJViewController () @end @implementation MJViewController - (void)viewDidLoad { [super viewDidLoad]; UploadFile *upload = [[UploadFile alloc] init]; NSString *urlString = @"http://localhost/upload.php"; NSString *path = [[NSBundle mainBundle] pathForResource:@"头像1.png" ofType:nil]; NSData *data = [NSData dataWithContentsOfFile:path]; [upload uploadFileWithURL:[NSURL URLWithString:urlString] data:data]; } @end [objc] view plain copy

// // UploadFile.m // 02.Post上传 // // Created by apple on 14-4-29. // Copyright (c) 2014年 itcast. All rights reserved. // #import "UploadFile.h" @implementation UploadFile // 拼接字符串 static NSString *boundaryStr = @"--"; // 分隔字符串 static NSString *randomIDStr; // 本次上传标示字符串 static NSString *uploadID; // 上传(php)脚本中，接收文件字段 - (instancetype)init { self = [super init]; if (self) { randomIDStr = @"itcast"; uploadID = @"uploadFile"; } return self; } #pragma mark - 私有方法 - (NSString *)topStringWithMimeType:(NSString *)mimeType uploadFile:(NSString *)uploadFile { NSMutableString *strM = [NSMutableString string]; [strM appendFormat:@"%@%@/n", boundaryStr, randomIDStr]; [strM appendFormat:@"Content-Disposition: form-data; name=/"%@/"; filename=/"%@/"/n", uploadID, uploadFile]; [strM appendFormat:@"Content-Type: %@/n/n", mimeType]; NSLog(@"%@", strM); return [strM copy]; } - (NSString *)bottomString { NSMutableString *strM = [NSMutableString string]; [strM appendFormat:@"%@%@/n", boundaryStr, randomIDStr]; [strM appendString:@"Content-Disposition: form-data; name=/"submit/"/n/n"]; [strM appendString:@"Submit/n"]; [strM appendFormat:@"%@%@--/n", boundaryStr, randomIDStr]; NSLog(@"%@", strM); return [strM copy]; } #pragma mark - 上传文件 - (void)uploadFileWithURL:(NSURL *)url data:(NSData *)data { // 1> 数据体 NSString *topStr = [self topStringWithMimeType:@"image/png" uploadFile:@"头像1.png"]; NSString *bottomStr = [self bottomString]; NSMutableData *dataM = [NSMutableData data]; [dataM appendData:[topStr dataUsingEncoding:NSUTF8StringEncoding]]; [dataM appendData:data]; [dataM appendData:[bottomStr dataUsingEncoding:NSUTF8StringEncoding]]; // 1. Request NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url cachePolicy:0 timeoutInterval:2.0f]; // dataM出了作用域就会被释放,因此不用copy request.HTTPBody = dataM; // 2> 设置Request的头属性 request.HTTPMethod = @"POST"; // 3> 设置Content-Length NSString *strLength = [NSString stringWithFormat:@"%ld", (long)dataM.length]; [request setValue:strLength forHTTPHeaderField:@"Content-Length"]; // 4> 设置Content-Type NSString *strContentType = [NSString stringWithFormat:@"multipart/form-data; boundary=%@", randomIDStr]; [request setValue:strContentType forHTTPHeaderField:@"Content-Type"]; // 3> 连接服务器发送请求 [NSURLConnection sendAsynchronousRequest:request queue:[[NSOperationQueue alloc] init] completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) { NSString *result = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]; NSLog(@"%@", result); }]; } @end

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