ios大文件下载封装

              1 #import <Foundation/Foundation.h>
  2  3@interface HMFileDownloader : NSObject
  4/**
  5 * 所需要下载文件的远程URL(连接服务器的路径)
  6*/  7 @property (nonatomic, copy) NSString *url;
  8/**
  9 * 文件的存储路径(文件下载到什么地方)
 10*/ 11 @property (nonatomic, copy) NSString *destPath;
 12 13/**
 14 * 是否正在下载(有没有在下载, 只有下载器内部才知道)
 15*/ 16 @property (nonatomic, readonly, getter = isDownloading) BOOL downloading;
 17 18/**
 19 * 用来监听下载进度
 20*/ 21 @property (nonatomic, copy) void (^progressHandler)(double progress);
 22/**
 23 * 用来监听下载完毕
 24*/ 25 @property (nonatomic, copy) void (^completionHandler)();
 26/**
 27 * 用来监听下载失败
 28*/ 29 @property (nonatomic, copy) void (^failureHandler)(NSError *error);
 30 31/**
 32 * 开始(恢复)下载
 33*/ 34 - (void)start;
 35 36/**
 37 * 暂停下载
 38*/ 39 - (void)pause;
 40 41@end
 42 43 44 45 #import "HMFileDownloader.h" 46 47 @interface HMFileDownloader() <NSURLConnectionDataDelegate>
 48/**
 49 * 连接对象
 50*/ 51 @property (nonatomic, strong) NSURLConnection *conn;
 52 53/**
 54 *  写数据的文件句柄
 55*/ 56 @property (nonatomic, strong) NSFileHandle *writeHandle;
 57/**
 58 *  当前已下载数据的长度
 59*/ 60 @property (nonatomic, assign) longlong currentLength;
 61/**
 62 *  完整文件的总长度
 63*/ 64 @property (nonatomic, assign) longlong totalLength;
 65@end
 66 67@implementation HMFileDownloader
 68 69/**
 70 * 开始(恢复)下载
 71*/ 72 - (void)start
 73{
 74     NSURL *url = [NSURL URLWithString:self.url];
 75// 默认就是GET请求 76     NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
 77// 设置请求头信息 78     NSString *value = [NSString stringWithFormat:@"bytes=%lld-", self.currentLength];
 79     [request setValue:value forHTTPHeaderField:@"Range"];
 80     self.conn = [NSURLConnection connectionWithRequest:request delegate:self];
 81 82     _downloading = YES;
 83}
 84 85/**
 86 * 暂停下载
 87*/ 88 - (void)pause
 89{
 90    [self.conn cancel];
 91     self.conn = nil;
 92 93     _downloading = NO;
 94}
 95 96#pragma mark - NSURLConnectionDataDelegate 代理方法
 97/**
 98 *  1. 当接受到服务器的响应(连通了服务器)就会调用
 99*/100 - (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
101{
102#warning 一定要判断
103if (self.totalLength) return;
104105// 1.创建一个空的文件到沙盒中106     NSFileManager *mgr = [NSFileManager defaultManager];
107// 刚创建完毕的大小是0字节108    [mgr createFileAtPath:self.destPath contents:nil attributes:nil];
109110// 2.创建写数据的文件句柄111     self.writeHandle = [NSFileHandle fileHandleForWritingAtPath:self.destPath];
112113// 3.获得完整文件的长度114     self.totalLength = response.expectedContentLength;
115}
116117/**
118 *  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)
119*/120 - (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
121{
122// 累加长度123     self.currentLength += data.length;
124125// 显示进度126double progress = (double)self.currentLength / self.totalLength;
127if (self.progressHandler) { // 传递进度值给block128        self.progressHandler(progress);
129    }
130131// 移动到文件的尾部132    [self.writeHandle seekToEndOfFile];
133// 从当前移动的位置(文件尾部)开始写入数据134    [self.writeHandle writeData:data];
135}
136137/**
138 *  3. 当服务器的数据接受完毕后就会调用
139*/140 - (void)connectionDidFinishLoading:(NSURLConnection *)connection
141{
142// 清空属性值143     self.currentLength = 0;
144     self.totalLength = 0;
145146if (self.currentLength == self.totalLength) {
147// 关闭连接(不再输入数据到文件中)148        [self.writeHandle closeFile];
149         self.writeHandle = nil;
150    }
151152if (self.completionHandler) {
153        self.completionHandler();
154    }
155}
156157/**
158 *  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)
159*/160 - (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
161{
162if (self.failureHandler) {
163        self.failureHandler(error);
164    }
165}
166167 @end

             1 #import "HMViewController.h" 2 #import "HMFileDownloader.h" 3 4@interface HMViewController ()
 5 @property (weak, nonatomic) IBOutlet UIProgressView *progressView;
 6 @property (nonatomic, strong) HMFileDownloader *fileDownloader;
 7 8 - (IBAction)start:(UIButton *)button;
 9@end
1011@implementation HMViewController
1213 - (HMFileDownloader *)fileDownloader
14{
15if (!_fileDownloader) {
16         _fileDownloader = [[HMFileDownloader alloc] init];
17// 需要下载的文件远程URL18         _fileDownloader.url = @"http://192.168.1.200:8080/MJServer/resources/jre.zip";
19// 文件保存到什么地方20         NSString *caches = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject];
21         NSString *filepath = [caches stringByAppendingPathComponent:@"jre.zip"];
22         _fileDownloader.destPath = filepath;
23//        typeof(10) a = 20; // int a = 20;2425         __weak typeof(self) vc = self;
26         _fileDownloader.progressHandler = ^(double progress) {
27             vc.progressView.progress = progress;
28        };
2930         _fileDownloader.completionHandler = ^{
31             NSLog(@"------下载完毕");
32        };
3334         _fileDownloader.failureHandler = ^(NSError *error){
3536        };
37    }
38return _fileDownloader;
39}
4041 - (void)viewDidLoad
42{
43    [super viewDidLoad];
4445}
4647// 按钮文字: "开始", "暂停"48 - (IBAction)start:(UIButton *)button { // self.currentLength == 20049if (self.fileDownloader.isDownloading) { // 暂停下载50        [self.fileDownloader pause];
5152         [button setTitle:@"恢复" forState:UIControlStateNormal];
53     } else { // 开始下载54        [self.fileDownloader start];
5556         [button setTitle:@"暂停" forState:UIControlStateNormal];
57    }
58}
5960 @end