if ([data length] > 0 && error == nil) {
NSLog(@"%lu bytes of data was returned.",(unsigned long)[data length]);
}else if([data length] == 0 && error == nil){
NSLog(@"No data was return.");
}else if (error != nil){
NSLog(@"Error happened = %@",error);
}
NSLog(@"We are done.");
}
/*
|
| as we know, it will chock main thread when we call sendSynchronousRequest on main thread,,,,change below
|
v
*/
//call sendSynchronousRequest on GCD pool
-(void)fetchYahooData2_GCD{
NSLog(@"We are here...");
NSString *urlString = @"http://www.easck.com/> NSLog(@"Firing synchronous url connection...");
dispatch_queue_t dispatchQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
dispatch_async(dispatchQueue, ^{
NSURL *url = [NSURL URLWithString:urlString];
NSURLRequest *urlRequest = [NSURLRequest requestWithURL:url];
NSURLResponse *response = nil;
NSError *error = nil;
NSData *data = [NSURLConnection sendSynchronousRequest:urlRequest returningResponse:&response error:&error];
if ([data length] > 0 && error == nil) {
NSLog(@"%lu bytes of data was returned.",(unsigned long)[data length]);
}else if ([data length] == 0 && error == nil){
NSLog(@"No data was returned.");
}else if (error != nil){
NSLog(@"Error happened = %@",error);
}
});
NSLog(@"We are done.");
}
查看运行输出结果，分别为：
synchronous download on main thread without GCD
