IOS自己封装的异步下载(get)Block方式回调给大家分享下

小牛一个希望大家多多关照。 上代码。

使用方法：造一个对象，调用

/**
 *  @brief  异步下载网络资源
 *
 *  @param  strURL URL连接(字符串形式)
 *  @param  updater block，下载成功调用的方法
 */
- (void)asynchronousDownload:(NSString *)url
                     success:(Success)success
                     failure:(Failure)failure;

方法。 
BLOCK 回调， 成功或失败。

#import

@class Downloader;

typedef void(^Success)(Downloader *downloader);
typedef void(^Failure)(NSError *error);

@interface Downloader : NSObject
{
    long double _length;
    NSMutableData *_datas;
}

@property (nonatomic, assign) long double length;
@property (nonatomic, strong) NSMutableData *datas;
@property (nonatomic, copy) Success success;
@property (nonatomic, copy) Failure failure;
@property (nonatomic, strong) NSString *strURL;

/**
 *  @brief  异步下载网络资源
 *
 *  @param  strURL URL连接(字符串形式)
 */
- (void)asynchronousDownload:(NSString *)url;

/**
 *  @brief  异步下载网络资源
 *
 *  @param  strURL URL连接(字符串形式)
 *  @param  updater block，下载成功调用的方法
 */
- (void)asynchronousDownload:(NSString *)url
                     success:(Success)success
                     failure:(Failure)failure;

@end

#import "Downloader.h"

@implementation Downloader

/**
 *  @brief  异步下载网络资源
 *
 *  @param  strURL URL连接(字符串形式)
 */
- (void)asynchronousDownload:(NSString *)strURL
{
    NSLog(@"--->> Downloader 开始下载");
    self.strURL = strURL;
    NSURL *url = [NSURL URLWithString:[strURL stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
    
    NSURLRequest *request = [NSURLRequest requestWithURL:url cachePolicy:NSURLRequestReloadIgnoringCacheData timeoutInterval:100];
    
    [NSURLConnection connectionWithRequest:request delegate:self];
}

/**
 *  @brief  异步下载网络资源
 *
 *  @param  strURL URL连接(字符串形式)
 *  @param  success block，下载成功调用的方法
 *  @param  failure block，下载失败调用的方法
 */
- (void)asynchronousDownload:(NSString *)url success:(Success)success failure:(Failure)failure
{
    self.success = success;
    self.failure = failure;
    
    [self asynchronousDownload:url];
}

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
    _length = response.expectedContentLength;
    _datas = [NSMutableData dataWithCapacity:_length];
}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
    [self.datas appendData:data];
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
    NSLog(@"--->> Downloader 下载完成");
    self.success(self);
}

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
    NSLog(@"\n----------------download error----------------- \n%@", error);
    self.failure(error);
}