今天写Http请求缓存的两个小bug

• 异常1
  hello world

Terminating app due to uncaught exception 'NSInternalInconsistencyException',
reason:
'-[__NSCFDictionary setObject:forKey:]:
mutating method sent to immutable object'

• 解决方法：
  将如下代码

NSData   *jsonData = 
[NSJSONSerialization
dataWithJSONObject:dictionary options:
NSJSONWritingPrettyPrinted error:&error];

改成：

NSData *jsonData ;
  if ([NSJSONSerialization isValidJSONObject:dictionary]) {
      jsonData = [NSJSONSerialization         dataWithJSONObject:dictionary
                options:0 error: &error];
      }

• 异常 2

Terminating app due to uncaught exception 'NSInternalInconsistencyException',
reason: '-[__NSCFDictionary setObject:forKey:]:
mutating method sent to immutable object'

将如下代码

 NSMutableDictionary *cacheDic = 
[USER_DEFAULT objectForKey:HttpExpiredCacheArrayKey];

改成

NSMutableDictionary *cacheDic =
[NSMutableDictionary dictionaryWithDictionary:
[USER_DEFAULT objectForKey:HttpExpiredCacheArrayKey]];