1.NSJSONReadingOptions
enum {
NSJSONReadingMutableContainers = (1UL << 0),
NSJSONReadingMutableLeaves = (1UL << 1),
NSJSONReadingAllowFragments = (1UL << 2)
};
typedef NSUInteger NSJSONReadingOptions;
2.解释
NSJSONReadingMutableContainers:
返回可变容器,NSMutableDictionary或NSMutableArray。
NSJSONReadingMutableLeaves:
返回的JSON对象中字符串的值为NSMutableString,目前在iOS 7上测试不好用,应该是个bug,参见: http://stackoverflow.com/questions/19345864/nsjsonreadingmutableleaves-option-is-not-working
NSJSONReadingAllowFragments:
允许JSON字符串最外层既不是NSArray也不是NSDictionary,但必须是有效的JSON Fragment。例如使用这个选项可以解析 @“123” 这样的字符串。参见: http://stackoverflow.com/questions/16961025/nsjsonserialization-nsjsonreadingallowfragments-reading