__NSCFNumber isEqualToString:的问题

  你在用到isEqualToString的地方先判断这个数据的类型
NSString *str;
if ( [object isKindOfClass:[NSNumber Class]])
{
    str = [object stringValue];
}
else if ([object isKindOfClass:[NSString Class]])
{
  str = object;
}

然后再进行你的[ str isEqualToString:...]...操作   

  NSLog(@"%@",[responseObject objectForKey:@"errorCode"]);

        NSString *str;
        if ( [[responseObject objectForKey:@"errorCode"] isKindOfClass:[NSNumber class]])
        {
            str = [[responseObject objectForKey:@"errorCode"] stringValue];
            if ([str isEqualToString:@"9997"]) {
                NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
                [defaults setObject:@"9997" forKey:@"errorCode"];
            }
        }else if ([[responseObject objectForKey:@"errorCode"] isKindOfClass:[NSString class]])
        {
            str = [responseObject objectForKey:@"errorCode"];
            NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
            [defaults setObject:@"9997" forKey:@"errorCode"];
        }