NSString *userStr = [bodyJson valueForKeyNullReplace:@"user"];
NSDictionary *userJson;
NSString *userJsonStr = [userStr JSONString];
userJson= [userJsonStr objectFromJSONString];
if (!userJson) {
userJson = [userStr JSONValue];
}
原文：http://www.cnblogs.com/guligei/p/3613398.html