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////  HMFileMultiDownloader.m//  08-多线程断点下载////  Created by apple on 14-6-27.//  Copyright (c) 2014年 heima. All rights reserved.//#import "HMFileMultiDownloader.h"#import "HMFileSingleDownloader.h"#define HMMaxDownloadCount 4@interface HMFileMultiDownloader()@property (nonatomic, strong) NSMutableArray *singleDownloaders;@property (nonatomic, assign) long long totalLength;@end@implementation HMFileMultiDownloader- (void)getFilesize{    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:self.url]];    request.HTTPMethod = @"HEAD";        NSURLResponse *response = nil;#warning 这里要用异步请求    [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:nil];    self.totalLength = response.expectedContentLength;}- (NSMutableArray *)singleDownloaders{    if (!_singleDownloaders) {        _singleDownloaders = [NSMutableArray array];                // 获得文件大小        [self getFilesize];                // 每条路径的下载量        long long size = 0;        if (self.totalLength % HMMaxDownloadCount == 0) {            size = self.totalLength / HMMaxDownloadCount;        } else {            size = self.totalLength / HMMaxDownloadCount + 1;        }                // 创建N个下载器        for (int i = 0; i

////  HMFileSingleDownloader.h//  08-多线程断点下载////  Created by apple on 14-6-27.//  Copyright (c) 2014年 heima. All rights reserved.//#import "HMFileDownloader.h"@interface HMFileSingleDownloader : HMFileDownloader/** *  开始的位置 */@property (nonatomic, assign) long long begin;/** *  结束的位置 */@property (nonatomic, assign) long long end; @end////  HMFileSingleDownloader.m//  08-多线程断点下载////  Created by apple on 14-6-27.//  Copyright (c) 2014年 heima. All rights reserved.//#import "HMFileSingleDownloader.h"@interface HMFileSingleDownloader() 
     
      /** * 连接对象 */@property (nonatomic, strong) NSURLConnection *conn;/** *  写数据的文件句柄 */@property (nonatomic, strong) NSFileHandle *writeHandle;/** *  当前已下载数据的长度 */@property (nonatomic, assign) long long currentLength;@end@implementation HMFileSingleDownloader- (NSFileHandle *)writeHandle{    if (!_writeHandle) {        _writeHandle = [NSFileHandle fileHandleForWritingAtPath:self.destPath];    }    return _writeHandle;}/** * 开始(恢复)下载 */- (void)start{    NSURL *url = [NSURL URLWithString:self.url];    // 默认就是GET请求    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];    // 设置请求头信息    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;}/** * 暂停下载 */- (void)pause{    [self.conn cancel];    self.conn = nil;        _downloading = NO;}#pragma mark - NSURLConnectionDataDelegate 代理方法/** *  1. 当接受到服务器的响应(连通了服务器)就会调用 */- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response{    }/** *  2. 当接受到服务器的数据就会调用(可能会被调用多次, 每次调用只会传递部分数据) */- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data{    // 移动到文件的尾部    [self.writeHandle seekToFileOffset:self.begin + self.currentLength];    // 从当前移动的位置(文件尾部)开始写入数据    [self.writeHandle writeData:data];        // 累加长度    self.currentLength += data.length;        // 打印下载进度    double progress = (double)self.currentLength / (self.end - self.begin);    if (self.progressHandler) {        self.progressHandler(progress);    }}/** *  3. 当服务器的数据接受完毕后就会调用 */- (void)connectionDidFinishLoading:(NSURLConnection *)connection{    // 清空属性值    self.currentLength = 0;        // 关闭连接(不再输入数据到文件中)    [self.writeHandle closeFile];    self.writeHandle = nil;}/** *  请求错误(失败)的时候调用(请求超时\断网\没有网, 一般指客户端错误) */- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error{    }@end
     

////  HMFileDownloader.h//  08-多线程断点下载////  Created by apple on 14-6-27.//  Copyright (c) 2014年 heima. All rights reserved.//#import 
     
      @interface HMFileDownloader : NSObject{    BOOL _downloading;}/** * 所需要下载文件的远程URL(连接服务器的路径) */@property (nonatomic, copy) NSString *url;/** * 文件的存储路径(文件下载到什么地方) */@property (nonatomic, copy) NSString *destPath;/** * 是否正在下载(有没有在下载, 只有下载器内部才知道) */@property (nonatomic, readonly, getter = isDownloading) BOOL downloading;/** * 用来监听下载进度 */@property (nonatomic, copy) void (^progressHandler)(double progress);/** * 开始(恢复)下载 */- (void)start;/** * 暂停下载 */- (void)pause;@end
     

 

 

////  HMViewController.m//  08-多线程断点下载////  Created by apple on 14-6-27.//  Copyright (c) 2014年 heima. All rights reserved.//#import "HMViewController.h"#import "HMFileMultiDownloader.h"@interface HMViewController ()@property (nonatomic, strong) HMFileMultiDownloader *fileMultiDownloader;@end@implementation HMViewController-  (HMFileMultiDownloader *)fileMultiDownloader{    if (!_fileMultiDownloader) {        _fileMultiDownloader = [[HMFileMultiDownloader alloc] init];        // 需要下载的文件远程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

 

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