文件的上傳
說明：文件上傳使用的時POST請求，通常把要上傳的數(shù)據(jù)保存在請求體中。本文介紹如何不借助第三方框架實現(xiàn)iOS開發(fā)中得文件上傳。
由于過程較為復(fù)雜，因此本文只貼出部分關(guān)鍵代碼。
主控制器的關(guān)鍵代碼：
YYViewController.m
#import "YYViewController.h"
#define YYEncode(str) [str dataUsingEncoding:NSUTF8StringEncoding]
@interface YYViewController ()
@end
@implementation YYViewController
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}
- (void)upload:(NSString *)name filename:(NSString *)filename mimeType:(NSString *)mimeType data:(NSData *)data parmas:(NSDictionary *)params
{
// 文件上傳
NSURL *url = [NSURL URLWithString:@"http://192.168.1.200:8080/YYServer/upload"];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
request.HTTPMethod = @"POST";
// 設(shè)置請求體
NSMutableData *body = [NSMutableData data];
/***************文件參數(shù)***************/
// 參數(shù)開始的標志
[body appendData:YYEncode(@"--YY/r/n")];
// name : 指定參數(shù)名(必須跟服務(wù)器端保持一致)
// filename : 文件名
NSString *disposition = [NSString stringWithFormat:@"Content-Disposition: form-data; name=/"%@/"; filename=/"%@/"/r/n", name, filename];
[body appendData:YYEncode(disposition)];
NSString *type = [NSString stringWithFormat:@"Content-Type: %@/r/n", mimeType];
[body appendData:YYEncode(type)];
[body appendData:YYEncode(@"/r/n")];
[body appendData:data];
[body appendData:YYEncode(@"/r/n")];
/***************普通參數(shù)***************/
[params enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {
// 參數(shù)開始的標志
[body appendData:YYEncode(@"--YY/r/n")];
NSString *disposition = [NSString stringWithFormat:@"Content-Disposition: form-data; name=/"%@/"/r/n", key];
[body appendData:YYEncode(disposition)];
[body appendData:YYEncode(@"/r/n")];
[body appendData:YYEncode(obj)];
[body appendData:YYEncode(@"/r/n")];
}];
/***************參數(shù)結(jié)束***************/
// YY--/r/n
[body appendData:YYEncode(@"--YY--/r/n")];
request.HTTPBody = body;
// 設(shè)置請求頭
// 請求體的長度
[request setValue:[NSString stringWithFormat:@"%zd", body.length] forHTTPHeaderField:@"Content-Length"];
// 聲明這個POST請求是個文件上傳
[request setValue:@"multipart/form-data; boundary=YY" forHTTPHeaderField:@"Content-Type"];
// 發(fā)送請求
[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) {
if (data) {
NSDictionary *dict = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableLeaves error:nil];
NSLog(@"%@", dict);
} else {
NSLog(@"上傳失敗");
}
}];
}
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
// Socket 實現(xiàn)斷點上傳
//apache-tomcat-6.0.41/conf/web.xml 查找 文件的 mimeType
// UIImage *image = [UIImage imageNamed:@"test"];
// NSData *filedata = UIImagePNGRepresentation(image);
// [self upload:@"file" filename:@"test.png" mimeType:@"image/png" data:filedata parmas:@{@"username" : @"123"}];
// 給本地文件發(fā)送一個請求
NSURL *fileurl = [[NSBundle mainBundle] URLForResource:@"itcast.txt" withExtension:nil];
NSURLRequest *request = [NSURLRequest requestWithURL:fileurl];
NSURLResponse *repsonse = nil;
NSData *data = [NSURLConnection sendSynchronousRequest:request returningResponse:&repsonse error:nil];
// 得到mimeType
NSLog(@"%@", repsonse.MIMEType);
[self upload:@"file" filename:@"itcast.txt" mimeType:repsonse.MIMEType data:data parmas:@{
@"username" : @"999",
@"type" : @"XML"}];
}
@end
補充說明：
文件上傳請求數(shù)據(jù)格式
部分文件的MIMEType
多線程斷點下載
說明：本文介紹多線程斷點下載。項目中使用了蘋果自帶的類，實現(xiàn)了同時開啟多條線程下載一個較大的文件。因為實現(xiàn)過程較為復(fù)雜，所以下面貼出完整的代碼。
實現(xiàn)思路：下載開始，創(chuàng)建一個和要下載的文件大小相同的文件（如果要下載的文件為100M，那么就在沙盒中創(chuàng)建一個100M的文件，然后計算每一段的下載量，開啟多條線程下載各段的數(shù)據(jù)，分別寫入對應(yīng)的文件部分）。
項目中用到的主要類如下：
完成的實現(xiàn)代碼如下：
主控制器中的代碼：
#import "YYViewController.h"
#import "YYFileMultiDownloader.h"
@interface YYViewController ()
@property (nonatomic, strong) YYFileMultiDownloader *fileMultiDownloader;
@end
@implementation YYViewController
- (YYFileMultiDownloader *)fileMultiDownloader
{
if (!_fileMultiDownloader) {
_fileMultiDownloader = [[YYFileMultiDownloader alloc] init];
// 需要下載的文件遠程URL
_fileMultiDownloader.url = @"http://192.168.1.200:8080/MJServer/resources/jre.zip";
// 文件保存到什么地方
NSString *caches = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject];
NSString *filepath = [caches stringByAppendingPathComponent:@"jre.zip"];
_fileMultiDownloader.destPath = filepath;
}
return _fileMultiDownloader;
}
- (void)viewDidLoad
{
[super viewDidLoad];
}
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
[self.fileMultiDownloader start];
}
@end
自定義一個基類
YYFileDownloader.h文件
#import <Foundation/Foundation.h>
@interface YYFileDownloader : NSObject
{
BOOL _downloading;
}
/**
* 所需要下載文件的遠程URL(連接服務(wù)器的路徑)
*/
@property (nonatomic, copy) NSString *url;
/**
* 文件的存儲路徑(文件下載到什么地方)
*/
@property (nonatomic, copy) NSString *destPath;
/**
* 是否正在下載(有沒有在下載, 只有下載器內(nèi)部才知道)
*/
@property (nonatomic, readonly, getter = isDownloading) BOOL downloading;
/**
* 用來監(jiān)聽下載進度
*/
@property (nonatomic, copy) void (^progressHandler)(double progress);
/**
* 開始(恢復(fù))下載
*/
- (void)start;
/**
* 暫停下載
*/
- (void)pause;
@end
YYFileDownloader.m文件
#import "YYFileDownloader.h"
@implementation YYFileDownloader
@end
下載器類繼承自YYFileDownloader這個類
YYFileSingDownloader.h文件
#import "YYFileDownloader.h"
@interface YYFileSingleDownloader : YYFileDownloader
/**
* 開始的位置
*/
@property (nonatomic, assign) long long begin;
/**
* 結(jié)束的位置
*/
@property (nonatomic, assign) long long end;
@end
YYFileSingDownloader.m文件
#import "YYFileSingleDownloader.h"
@interface YYFileSingleDownloader() <NSURLConnectionDataDelegate>
/**
* 連接對象
*/
@property (nonatomic, strong) NSURLConnection *conn;
/**
* 寫數(shù)據(jù)的文件句柄
*/
@property (nonatomic, strong) NSFileHandle *writeHandle;
/**
* 當前已下載數(shù)據(jù)的長度
*/
@property (nonatomic, assign) long long currentLength;
@end
@implementation YYFileSingleDownloader
- (NSFileHandle *)writeHandle
{
if (!_writeHandle) {
_writeHandle = [NSFileHandle fileHandleForWritingAtPath:self.destPath];
}
return _writeHandle;
}
/**
* 開始(恢復(fù))下載
*/
- (void)start
{
NSURL *url = [NSURL URLWithString:self.url];
// 默認就是GET請求
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
// 設(shè)置請求頭信息
NSString *value = [NSString stringWithFormat:@"bytes=%lld-%lld", self.begin + self.currentLength, self.end];
[request setValue:value forHTTPHeaderField:@"Range"];
self.conn = [NSURLConnection connectionWithRequest:request delegate:self];
_downloading = YES;
}
/**
* 暫停下載
*/
- (void)pause
{
[self.conn cancel];
self.conn = nil;
_downloading = NO;
}
#pragma mark - NSURLConnectionDataDelegate 代理方法
/**
* 1. 當接受到服務(wù)器的響應(yīng)(連通了服務(wù)器)就會調(diào)用
*/
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
}
/**
* 2. 當接受到服務(wù)器的數(shù)據(jù)就會調(diào)用(可能會被調(diào)用多次, 每次調(diào)用只會傳遞部分數(shù)據(jù))
*/
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
// 移動到文件的尾部
[self.writeHandle seekToFileOffset:self.begin + self.currentLength];
// 從當前移動的位置(文件尾部)開始寫入數(shù)據(jù)
[self.writeHandle writeData:data];
// 累加長度
self.currentLength += data.length;
// 打印下載進度
double progress = (double)self.currentLength / (self.end - self.begin);
if (self.progressHandler) {
self.progressHandler(progress);
}
}
/**
* 3. 當服務(wù)器的數(shù)據(jù)接受完畢后就會調(diào)用
*/
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
// 清空屬性值
self.currentLength = 0;
// 關(guān)閉連接(不再輸入數(shù)據(jù)到文件中)
[self.writeHandle closeFile];
self.writeHandle = nil;
}
/**
* 請求錯誤(失敗)的時候調(diào)用(請求超時/斷網(wǎng)/沒有網(wǎng), 一般指客戶端錯誤)
*/
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
}
@end
設(shè)計多線程下載器(利用HMFileMultiDownloader能開啟多個線程同時下載一個文件)
一個多線程下載器只下載一個文件
YYFileMultiDownloader.h文件
#import "YYFileDownloader.h"
@interface YYFileMultiDownloader : YYFileDownloader
@end
YYFileMultiDownloader.m文件
#import "YYFileMultiDownloader.h"
#import "YYFileSingleDownloader.h"
#define YYMaxDownloadCount 4
@interface YYFileMultiDownloader()
@property (nonatomic, strong) NSMutableArray *singleDownloaders;
@property (nonatomic, assign) long long totalLength;
@end
@implementation YYFileMultiDownloader
- (void)getFilesize
{
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:self.url]];
request.HTTPMethod = @"HEAD";
NSURLResponse *response = nil;
#warning 這里要用異步請求
[NSURLConnection sendSynchronousRequest:request returningResponse:&response error:nil];
self.totalLength = response.expectedContentLength;
}
- (NSMutableArray *)singleDownloaders
{
if (!_singleDownloaders) {
_singleDownloaders = [NSMutableArray array];
// 獲得文件大小
[self getFilesize];
// 每條路徑的下載量
long long size = 0;
if (self.totalLength % YYMaxDownloadCount == 0) {
size = self.totalLength / YYMaxDownloadCount;
} else {
size = self.totalLength / YYMaxDownloadCount + 1;
}
// 創(chuàng)建N個下載器
for (int i = 0; i<YYMaxDownloadCount; i++) {
YYFileSingleDownloader *singleDownloader = [[YYFileSingleDownloader alloc] init];
singleDownloader.url = self.url;
singleDownloader.destPath = self.destPath;
singleDownloader.begin = i * size;
singleDownloader.end = singleDownloader.begin + size - 1;
singleDownloader.progressHandler = ^(double progress){
NSLog(@"%d --- %f", i, progress);
};
[_singleDownloaders addObject:singleDownloader];
}
// 創(chuàng)建一個跟服務(wù)器文件等大小的臨時文件
[[NSFileManager defaultManager] createFileAtPath:self.destPath contents:nil attributes:nil];
// 讓self.destPath文件的長度是self.totalLengt
NSFileHandle *handle = [NSFileHandle fileHandleForWritingAtPath:self.destPath];
[handle truncateFileAtOffset:self.totalLength];
}
return _singleDownloaders;
}
/**
* 開始(恢復(fù))下載
*/
- (void)start
{
[self.singleDownloaders makeObjectsPerformSelector:@selector(start)];
_downloading = YES;
}
/**
* 暫停下載
*/
- (void)pause
{
[self.singleDownloaders makeObjectsPerformSelector:@selector(pause)];
_downloading = NO;
}
@end
補充說明：如何獲得將要下載的文件的大小？
