Objective中更好的JSON解析实现

我正在接收JSON响应，以便在核心数据中保存用户首选项。

preferences={
      1={
        children=({
          3=Samsung;4=Nokia;
        });id=1;name=Mobiles;
      };2={
        children=({
          5="Samsung Curve TV";
        });id=2;name=Electronics;
      };
    };

这是我的代码片段，它工作正常。 但我认为这是非常冗长的代码。

    NSLog(@"Preferences: %@", [response objectForKey:@"preferences"]);

    for (NSDictionary *dic in [response objectForKey:@"preferences"]) {
        NSLog(@"ID: %@", [[[response objectForKey:@"preferences"] objectForKey:dic] objectForKey:@"id"]);
        NSLog(@"NAME: %@", [[[response objectForKey:@"preferences"] objectForKey:dic] objectForKey:@"name"]);

        NSLog(@"Children DIC: %@", [[[[[response objectForKey:@"preferences"]
                                     objectForKey:dic] objectForKey:@"children"] objectAtIndex:0] objectForKey:@"3"]);

        for (NSDictionary *childDic in [[[[response objectForKey:@"preferences"]
                                          objectForKey:dic] objectForKey:@"children"] objectAtIndex:0]) {
            NSLog(@"Child Name: %@", [[[[[response objectForKey:@"preferences"]
                                        objectForKey:dic] objectForKey:@"children"] objectAtIndex:0] objectForKey:childDic]);
        }
    }

我有3个问题。

我该如何改进我的代码片段？ 有没有更简单的方法来实现这一点？

这个JSON响应是否足够用于移动端解析？ 它是不错的JSON格式？ 在使用核心数据方面，是否有任何JSON响应格式作为移动开发人员应遵循（它们只是将数据库实现作为最佳实践减少）？

我如何从Objective-c中再次构造这样的JSON字符串？

---

好吧，（对不起，没有深入的分析）首先我要修改你的JSON不要包含动态元素的dictionary （samsung有关键3等等，它应该是数组，有道理？）

我拿出更好的JSON结构：

{  
   "preferences":[
      {
         "items":[
            {
            "id" : "3",
            "name" : "Samsung" 
            },
            {
            "id" : "3",
            "name" : "Nokia" 
            }
         ],
         "id":"1",
         "name":"Mobiles"
      },
      {  
         "items":[
           {
            "id" : "3",
            "name" : "Nokia" 
            }
         ],
         "id":"2",
         "name":"Electronics"
      }
]
}

现在使用JSONModel将其映射到对象是非常容易的，只有一件您应该关心的是映射键。

 NSString *JSONString = @"    {        "preferences":[        {            "items":[            {                "id" : "3",                "name" : "Samsung"            },            {                "id" : "3",                "name" : "Nokia"            }            ],            "id":"1",            "name":"Mobiles"        },        {            "items":[            {                "id" : "3",                "name" : "Nokia"            }            ],            "id":"2",            "name":"Electronics"        }        ]    }";


    NSDictionary *dictionary = [NSJSONSerialization JSONObjectWithData:[JSONString dataUsingEncoding:NSUTF8StringEncoding] options:0 error:nil];

    NSError *mapError;
    GlobalPreferences *globalPreferences = [[GlobalPreferences alloc] initWithDictionary:dictionary error:&mapError];
    if (mapError) {
        NSLog(@"Something went wrong with mapping model %@", mapError);
    }

    NSLog(@"Your mapped model: %@", globalPreferences);

楷模：

Kinda GlobalPreference，根模型，以防万一你决定添加额外的东西

 #import <JSONModel/JSONModel.h>
    #import "Preference.h"

    @interface GlobalPreferences : JSONModel

    @property (nonatomic, strong) NSArray<Preference> *preferences; // using protocol here you specifying to which model data should be mapped
    @property (nonatomic, strong) NSArray<Optional> *somethingElse; // some other settings may be here

    @end

    #import "GlobalPreferences.h"

    @implementation GlobalPreferences

    @end

偏爱

#import <JSONModel/JSONModel.h>
  #import "PreferenceItem.h"

    @protocol Preference <NSObject>

    @end

    @interface Preference : JSONModel

    @property (nonatomic, strong) NSNumber *ID; // required
    @property (nonatomic, strong) NSString *name; // required
    @property (nonatomic, strong) NSArray<PreferenceItem> *items;

    @end

    #import "Preference.h"

    @implementation Preference

    #pragma mark - JSONModel

    + (JSONKeyMapper *)keyMapper {
        return [[JSONKeyMapper alloc] initWithDictionary:@{
                                                           @"id": @"ID",
                                                           }];
    }

    @end

PreferenceItem

    #import <JSONModel/JSONModel.h>

    // This protocol just to let JSONModel know to which model needs to be parsed data in case if it's an array/dictionary
    @protocol PreferenceItem <NSObject>
    @end

@interface PreferenceItem : JSONModel

@property (nonatomic, strong) NSNumber *ID;
@property (nonatomic, strong) NSString *name;

@end
#import "PreferenceItem.h"

@implementation PreferenceItem

#pragma mark - JSONModel

+ (JSONKeyMapper *)keyMapper {
    return [[JSONKeyMapper alloc] initWithDictionary:@{
                                                       @"id": @"ID",
                                                       }];
}

@end

对于coreData应该coreData 。

也许对于你来说，所有这些都不是必须的，但是当你解析/映射网络响应（比如data types ， missing keys ， error handling等等）时，你需要关心很多事情。 如果你手动映射 - 你有可能在某天破坏应用程序。

---

我知道你问了Objective-C的最佳实践，但我建议切换到Swift并使用SwiftyJSON。 使用Swift，代码比Objective-C更可读。

let prefs = json["preferences"]
let userName = prefs["id"].stringValue
let name = prefs["name"].stringValue
let child = prefs["children"].arrayValue[0].arrayValue[3]

https://github.com/SwiftyJSON/SwiftyJSON

您可以轻松构建自己的JSON结构并使用Alamofire发送它们：

let parameters: [String : AnyObject] = [
  "preferences": [
    "id": "123",
    "name": "John",
    "children": [
       ["3": "Three"]
    ]
  ]
]

let urlReq = NSMutableURLRequest(url)
urlReq.HTTPMethod = .POST

let req = Alamofire.ParameterEncoding.JSON.encode(urlReq, parameters: parameters).0
let request = Alamofire.request(req)

https://github.com/Alamofire/Alamofire

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