您也可以通过在调试器中输入以下内容即时执行此操作

po [[NSString alloc] initWithData:[NSJSONSerialization dataWithJSONObject:yourDictionary options:1 error:nil] encoding:4];

从ISO7开始，至少你可以用NSJSONSerialization轻松做到这一点。

将NSDictionary转换为NSString:

NSError * err;
NSData * jsonData = [NSJSONSerialization dataWithJSONObject:myDictionary options:0 error:&err]; 
NSString * myString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];

在Swift 2.0版本中:

class func jsonStringWithJSONObject(jsonObject: AnyObject) throws -> String? {
    let data: NSData? = try? NSJSONSerialization.dataWithJSONObject(jsonObject, options: NSJSONWritingOptions.PrettyPrinted)

    var jsonStr: String?
    if data != nil {
        jsonStr = String(data: data!, encoding: NSUTF8StringEncoding)
    }

    return jsonStr
}

这将在swift4和swift5中工作。

let dataDict = "the dictionary you want to convert in jsonString" 

let jsonData = try! JSONSerialization.data(withJSONObject: dataDict, options: JSONSerialization.WritingOptions.prettyPrinted)

let jsonString = NSString(data: jsonData, encoding: String.Encoding.utf8.rawValue)! as String

print(jsonString)

现在不需要第三方类ios 5引入了Nsjsonserialization

NSString *urlString=@"Your url";
NSString *urlUTF8 = [urlString stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSURL *url=[[NSURL alloc]initWithString:urlUTF8];
NSURLRequest *request=[NSURLRequest requestWithURL:url];

NSURLResponse *response;

NSData *GETReply = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:nil];

NSError *myError = nil;

NSDictionary *res = [NSJSONSerialization JSONObjectWithData:GETReply options:NSJSONReadingMutableLeaves|| NSJSONReadingMutableContainers error:&myError];

Nslog(@"%@",res);

这段代码对于获取jsondata非常有用。