ios - iOS 5 HTTP查询与JSON对象

Question

在iOS 5上，如何使用JSON对象查询Web服务？
我尝试了许多不同的方法，但无法使其正常工作。看来AFNetworking或RestKit框架是最简单的途径，但是我都没有经验。我也是iOS开发的新手。

这是一个有效的示例查询:

https://site.com/gis?QUERY={"ARGUMENTS":{"TO":{"OBJECT_TYPE":"BUILDING","OBJECT_ID":"1","TYPE":"IDENTIFIER"},"FROM":{"OBJECT_TYPE":"BUILDING","OBJECT_ID":"2","TYPE":"IDENTIFIER"},"PATHTYPES":["SIDEWALK"},"QUERYTYPE":"FINDPATH"}

Answer 1

创建一个url请求，请参见下面的示例。这将发布json数据。在您的情况下，您使用的是GET http方法，因此您无需发布json数据，只需将其包含在url中即可。请注意，我的一些变量声明未显示。

NSArray *keys = [NSArray arrayWithObjects:@"longitude", @"latitude", nil];
NSArray *objects = [NSArray arrayWithObjects:longitude, latitude, nil];

NSDictionary *jsonDictionary = [NSDictionary dictionaryWithObjects:objects forKeys:keys];

if([NSJSONSerialization isValidJSONObject:jsonDictionary])
{
    __jsonData = [NSJSONSerialization dataWithJSONObject:jsonDictionary options:0 error:nil];
    __jsonString = [[NSString alloc]initWithData:__jsonData encoding:NSUTF8StringEncoding];
}

// Be sure to properly escape your url string.
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:@"https://site.com...etc"];
[request setHTTPMethod:@"POST"];
[request setHTTPBody: __jsonData];
[request setValue:@"application/json" forHTTPHeaderField:@"Content-Type"];
[request setValue:[NSString stringWithFormat:@"%d", [__jsonData length]] forHTTPHeaderField:@"Content-Length"];  

NSError *errorReturned = nil;
NSURLResponse *theResponse =[[NSURLResponse alloc]init];
NSData *data = [NSURLConnection sendSynchronousRequest:request returningResponse:&theResponse error:&errorReturned];

if (errorReturned) {
    // Handle error.
}
else
{
    NSError *jsonParsingError = nil;
    NSArray *jsonArray = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableContainers|NSJSONReadingAllowFragments error:&jsonParsingError];
}