NSURLConnection的文件或者图片下载

NSURLConnection的文件或者图片下载：
//@property (nonatomic,
strong) NSMutableData *mutableData;
//得到url
NSURL *url = [NSURL
URLWithString:[self.updateContentDict
valueForKey:@"commons"]];
NSMutableURLRequest *request = [[NSMutableURLRequest
alloc] init];
[request setURL:url];
[request setHTTPMethod:@"GET"];
//设置请求方式
[request setTimeoutInterval:30];//设置超时时间
self.mutableData = [[NSMutableData
alloc] init];
[self.view
makeToast:@"app下载中..."];
[NSURLConnection
connectionWithRequest:request
delegate:self];//发送一个异步请求

//Controller须实现NSURLConnectionDataDelegate协议
然后实现以下3个方法

#pragma mark - NSURLConnection delegate
//数据加载过程中调用,获取数据
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
[self.mutableData
appendData:data];
NSLog(@"%@",self.mutableData);
}

//数据加载完成后调用
- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
[self
dismissHUD];
[self.view
makeToast:@"下载完成"];
}

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
NSLog(@"请求网络失败:%@",error);
}
//以上例子是吧数据放在属性的NSMutableData里面