//字典轉化json

NSDictionary * jsonDic = [NSDictionarydictionaryWithObjects:@[@"100",@"99",@"98"]forKeys:@[@"a",@"b",@"c"]];

NSData * jsonData = [NSJSONSerializationdataWithJSONObject:jsonDic options:NSJSONWritingPrettyPrintederror:nil];

NSString * jsonString = [[NSStringalloc] initWithData:jsonData encoding

//json轉化字典（json解析）

NSDictionary  * dic  = [NSJSONSerializationJSONObjectWithData:[jsonString dataUsingEncoding:NSUTF8StringEncoding] options:NSJSONReadingMutableContainerserror:nil];

//陣列轉化json

//    NSArray * jsonArr = [NSArray arrayWithObjects:@"1",@"2",@"3", nil];

//    NSData * jsonData = [NSJSONSerialization dataWithJSONObject:jsonArr options:NSJSONWritingPrettyPrinted error:nil];

//    NSString * jsonString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];

//json轉化陣列

//    NSArray  * arr  = [NSJSONSerialization JSONObjectWithData:[jsonString dataUsingEncoding:NSUTF8StringEncoding] options:NSJSONReadingMutableContainers error:nil];

關於NSJSONWritingPrettyPrinted