Question

我很难尝试从NSURLConnection请求接收JSON。任何人都可以提供任何建议吗？我无法理解为什么JSON没有出现

编辑：当我将端点/书籍附加到url字符串的末尾时，我得到了这个JSON响应：“json NSDictionary * 0键/值对。”这是否意味着服务器中没有任何内容？

-(void)makeLibraryRequests
{
    NSURL *url = [NSURL URLWithString:@"http://prolific-interview.herokuapp.com/54bexxxxxxxxxxxxxxxxaa56"];
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url]; //;]cachePolicy:NSURLRequestReloadIgnoringCacheData timeoutInterval:20.0f];
    [request setHTTPMethod:@"GET"];
//    This is actually how jQuery works. If you don't tell it what to do with the result, it uses the Content-type to detect what to do with it.
    [request setValue:@"application/json" forHTTPHeaderField:@"Accept"];
    [request setValue:@"application/json" forHTTPHeaderField:@"Content-Type"];
//[request setValue:@"application/json; charset=UTF-8" forHTTPHeaderField:@"Content-Type"];
    [NSURLConnection sendAsynchronousRequest:request queue:[[NSOperationQueue alloc]init] completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) {

    //parse data here!!

    NSError *jsonError;
    NSDictionary *json = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&jsonError];

    if (json) {
        //NSArray *allBooks = [json objectForKey:@"books"];

        //create your MutableArray here

        dispatch_async(dispatch_get_main_queue(), ^{
            [self.tableView reloadData];
        });
    }
    else{
        NSLog(@"error occured %@", jsonError);

        NSString *serverResponse = [[NSString alloc] initWithData:data encoding:NSASCIIStringEncoding];

        NSLog(@"\n\nError:\n%@\n\nServer Response:\n%@\n\nCrash:", jsonError.description, serverResponse);
        //[NSException raise:@"Invalid Data" format:@"Unable to process web server response."];
    }

}];

}

Answer 1

正如YiPing所指出的，您必须提供books终点。但是在你第一次发书之前，你不会有任何东西。

NSDictionary *params = @{@"author": @"Diego Torres Milano",
                         @"categories" : @"android,testing",
                         @"title": @"Android Application Testing Guide",
                         @"publisher": @"Packt Publishing",
                         @"lastCheckedOutBy": @"Joe"};

NSURL *url = [NSURL URLWithString:@"http://prolific-interview.herokuapp.com/54bexxxxxxxxxxxxxaa56/books/"];  // your id removed for security's sake ... put it back in
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
[request setHTTPMethod:@"POST"];
[request setValue:@"application/json" forHTTPHeaderField:@"Accept"];
[request setValue:@"application/json" forHTTPHeaderField:@"Content-Type"];
NSError *encodeError;
NSData *body = [NSJSONSerialization dataWithJSONObject:params options:0 error:&encodeError];
NSAssert(body, @"JSON encode failed: %@", encodeError);
request.HTTPBody = body;

因此，首先POST使用上述请求的书籍，然后您的原始GET（假设您添加结束点）现在将返回结果。

Answer 2

在您的网址中添加一些端点

试试这个：

http://prolific-interview.herokuapp.com/54bexxxxxxxxxxxxxxxxaa56/books/

使用NSURLConnection从GET请求接收JSON很困难

2 个答案: