[iOS] 取回HTML (UTF-8)

    NSURL *URL = [NSURL URLWithString:@"http://example.com/"];
    NSURLRequest *request = [NSURLRequest requestWithURL:URL];
    AFHTTPRequestOperation *op = [[AFHTTPRequestOperation alloc] initWithRequest:request];
    op.responseSerializer.acceptableContentTypes = [NSSet setWithObject:@"text/html"];
    op.responseSerializer =[AFHTTPResponseSerializer serializer];
    [op setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
//      NSString* newStr = [NSString stringWithUTF8String:[responseObject bytes]];
        NSString* newStr = [[NSString alloc] initWithData:responseObject encoding:NSUTF8StringEncoding];
        NSLog(@"HTML: %@", newStr);
    } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
        NSLog(@"Error: %@", error);
    }];
    [[NSOperationQueue mainQueue] addOperation:op];