2016 - 1- 24 大文件下载 关于NSOutStream 的使用补充

//
//  ViewController.m
//  大文件下载
//
//  Created by Mac on 16/1/24.
//  Copyright © 2016年 Mac. All rights reserved.
//

#import "ViewController.h"

@interface ViewController ()<NSURLConnectionDataDelegate>

// 输出流
@property (nonatomic, strong) NSOutputStream *stream;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    NSURL *url = [NSURL URLWithString:@"http://120.25.226.186:32812/resources/videos/minion_15.mp4"];

    NSURLRequest *request = [NSURLRequest requestWithURL:url];

    [NSURLConnection connectionWithRequest:request delegate:self];

}

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response{

//    response.suggestedFilename  ------  建议文件名，与服务器上的文件名保持一致

    // 获得文件路径
    NSString *str = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject];
    NSString *file = [str stringByAppendingString:response.suggestedFilename];
    NSLog(@"%@",file);

    // 写入到文件路径，append:YES 表示每次写入都写入当前文件的尾部
    self.stream = [[NSOutputStream alloc] initToFileAtPath:file append:YES];

    // 如果文件不存在会自己创建一个新的,注意这一步很重要
    [self.stream open];

}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data{

    // 写入文件
    [self.stream write:[data bytes] maxLength:data.length];
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection{

    // 完成下载,关闭stream
    [self.stream close];
    self.stream = nil;
    NSLog(@"------");

}

@end