objective-c - What is the reason why there are null and duplicates when traversing NSDictionary in iOS?

Question

When I parse JSON, null and duplicate data will appear when traversing the dictionary content to the model in the last step. Every previous step is correct. I have this problem when I test the api of a friend's own server. I also used the news API in Baidu APIStore and had the same problem. Please tell me what I did wrong. Please enlighten me. Thank you!

The following is the code, using AFNetworking, there are 5 arrays in JSON, and the bottom is a screenshot of the console, using a for loop and a commented out for in, both have the same problem

    [manager POST:@"地址不便透露，抱歉" parameters:parameters progress:nil success:^(NSURLSessionDataTask * _Nonnull task, id  _Nullable responseObject) {
        NSLog(@"成功");
        if ([responseObject isKindOfClass:[NSDictionary class]]) {
            NSArray *jData = [responseObject objectForKey:@"array"];
            //NSLog(@"%@",jData);
            
            for (NSDictionary * dict in jData)
            {
                NSArray * keys=[dict allKeys];
                JKey * jKey=[[JKey alloc]init];
                /*
                for (NSString * str in keys) {
                    //对对象的属性一一赋值 KVC
                    [jKey setValue:[dict objectForKey:str] forKey:str];
                    if ([dict objectForKey:str] > 0) {
                        [self.testArray addObject:jKey];
                    }
                }
                 */
                for (NSInteger i=0; i<keys.count; i++) {
                    [jKey setValue:[dict objectForKey:keys[i]] forKey:keys[i]];
                    NSLog(@"jKey=%@",jKey.coverpath);
                }
            }
        }

Answer 1

I tried it myself and it was no problem to assign values ​​one by one

for (NSDictionary * dict in jData)
{
    JKey * jKey=[[JKey alloc]init];
    jKey.title = [dict valueForKey:@"title"];
    jKey.link = [dict valueForKey:@"link"];
    jKey.Id = [dict valueForKey:@"id"];
    jKey.coverpath = [dict valueForKey:@"coverpath"];
    [self.testArray addObject:jKey];
}

Answer 2

Try it with MJExtension
for (NSInteger i = 0; i<array1.count; i++) {

     NormalModel * model = [NormalModel  objectWithKeyValues:array1[i]];
    
    [self.dataArray addObject:model];
}