IOS JsonModel的学习及使用
当我们从服务端获取到json数据后的时候，我们需要在界面上展示或者保存起来，下面来看下直接通过NSDictionary取出数据的情况。
NSDictionary直接取出数据的诟病。
NSString *name = [self.responseObj objectForKey:@"name"];NSString *gender = [self.responseObj objectForKey:@"gender"];NSString *sign = [self.responseObj objectForKey:@"sign"];NSString *avatar = [self.responseObj objectForKey:@"avatar"];NSString *phone = [self.responseObj objectForKey:@"phone"];NSString *token = [self.responseObj objectForKey:@"token"];从以上的代码，我们能够看出，取出数据相当繁琐的。为了防止显示及出现crash等问题，还需要判断值的nil，null，类型等情况的出现。
所以我们需要使用到JSONModel。
简介JSONModel
JSONModel - 神奇的JSON数据建模框架 https://github.com/jsonmodel/jsonmodel
JSONModel可以快速创建智能数据模型。你可以在你的iOS，MacOS和watchOS和tvOS应用程序使用它。自动将JSON转成你的模型类，大大减少你需要编写的代码量。
见http://www.laileshuo.com/?p=669查看关于更改的详细信息。
（图片来源于网络）
JSONModel安装(Installation)
- 使用CocoaPods安装，在podfile，添加一下内容，之后使用pod update更新
pod 'JSONModel'- 使用Carthage安装
github "jsonmodel/jsonmodel"JSONModel使用手册(Manual)
- 下载JSONModel库
- 复制JSONModel子文件夹到您的Xcode项目
- 添加SystemConfiguration.framework库
JSONModel基础用法(Basic Usage)
假设你的JSON格式是这样的：
{ "id": 10, "country": "Germany", "dialCode": 49, "isInEurope": true }- 创建一个JSONModel的子类
- 在.h头文件中声明一些以json的key命名的属性
@interface CountryModel : JSONModel@property (nonatomic) NSInteger id;@property (nonatomic) NSString *country;@property (nonatomic) NSString *dialCode;@property (nonatomic) BOOL isInEurope;@end之后我们没有必要在.m文件中多做什么特殊的处理。
初始化数据模型：
NSError *error;CountryModel *country = [[CountryModel alloc] initWithString:myJson error:&error];如果验证JSON通过的话，将会通过json中的key的value值为CountryModel的id，country，dialCode，isInEurope的属性赋值。并且自动匹配相遇的类型。
实例
自动根据名称映射
{"id": 123,"name": "Product name","price": 12.95} @interface ProductModel : JSONModel@property (nonatomic) NSInteger id;@property (nonatomic) NSString *name;@property (nonatomic) float price;@end模型嵌套 (模型包含其他模型)
{"orderId": 104,"totalPrice": 13.45,"product": {"id": 123,"name": "Product name","price": 12.95}} @interface ProductModel : JSONModel@property (nonatomic) NSInteger id;@property (nonatomic) NSString *name;@property (nonatomic) float price;@end@interface OrderModel : JSONModel@property (nonatomic) NSInteger orderId;@property (nonatomic) float totalPrice;@property (nonatomic) ProductModel *product;@end模型集合collections
{"orderId": 104,"totalPrice": 103.45,"products": [{"id": 123,"name": "Product #1","price": 12.95},{"id": 137,"name": "Product #2","price": 82.95}]} @protocol ProductModel;@interface ProductModel : JSONModel@property (nonatomic) NSInteger id;@property (nonatomic) NSString *name;@property (nonatomic) float price;@end@interface OrderModel : JSONModel@property (nonatomic) NSInteger orderId;@property (nonatomic) float totalPrice;@property (nonatomic) NSArray <ProductModel> *products;@end注：NSArray的后尖括号包含的协议。这是不一样的目标C泛型系统。它们不是相互排斥的，而是为JSONModel工作，该协议必须到位。
嵌套键映射
{"orderId": 104,"orderDetails": [{"name": "Product #1","price": {"usd": 12.95}}]}
@interface OrderModel : JSONModel
@property (nonatomic) NSInteger id;
@property (nonatomic) NSString *productName;
@property (nonatomic) float price;
@end@implementation OrderModel+ (JSONKeyMapper *)keyMapper
{return [[JSONKeyMapper alloc] initWithModelToJSONDictionary:@{@"id": @"orderId",@"productName": @"orderDetails.name",@"price": @"orderDetails.price.usd"}];
}@end自动映射到snake_case
{"order_id": 104,"order_product": "Product #1","order_price": 12.95
}
@interface OrderModel : JSONModel
@property (nonatomic) NSInteger orderId;
@property (nonatomic) NSString *orderProduct;
@property (nonatomic) float orderPrice;
@end@implementation OrderModel+ (JSONKeyMapper *)keyMapper
{return [JSONKeyMapper mapperForSnakeCase];
}@end可选属性Optional (就是说这个属性可以为null或者为空)
{"id": 123,"name": null,"price": 12.95
}@interface ProductModel : JSONModel
@property (nonatomic) NSInteger id;
@property (nonatomic) NSString <Optional> *name;
@property (nonatomic) float price;
@property (nonatomic) NSNumber <Optional> *uuid;
@end忽略属性 Ignored (就是JSONModel完全忽略这个属性)
{"id": 123,"name": null
}@interface ProductModel : JSONModel
@property (nonatomic) NSInteger id;
@property (nonatomic) NSString <Ignore> *customProperty;
@end设置标量类型可选optional
{"id": null
}@interface ProductModel : JSONModel
@property (nonatomic) NSInteger id;
@end@implementation ProductModel+ (BOOL)propertyIsOptional:(NSString *)propertyName
{if ([propertyName isEqualToString:@"id"])return YES;return NO;
}@end将model转成json
ProductModel *pm = [ProductModel new];
pm.name = @"Some Name";// convert to dictionary
NSDictionary *dict = [pm toDictionary];// convert to json
NSString *string = [pm toJSONString];特定类型数据转换
@interface JSONValueTransformer (CustomNSDate)
@end@implementation JSONValueTransformer (CustomTransformer)- (NSDate *)NSDateFromNSString:(NSString *)string
{NSDateFormatter *formatter = [NSDateFormatter new];formatter.dateFormat = APIDateFormat;return [formatter dateFromString:string];
}- (NSString *)JSONObjectFromNSDate:(NSDate *)date
{NSDateFormatter *formatter = [NSDateFormatter new];formatter.dateFormat = APIDateFormat;return [formatter stringFromDate:date];
}@end自定义 getters/setters
@interface ProductModel : JSONModel
@property (nonatomic) NSInteger id;
@property (nonatomic) NSString *name;
@property (nonatomic) float price;
@property (nonatomic) NSLocale *locale;
@end@implementation ProductModel- (void)setLocaleWithNSString:(NSString *)string
{self.locale = [NSLocale localeWithLocaleIdentifier:string];
}- (void)setLocaleWithNSDictionary:(NSDictionary *)dictionary
{self.locale = [NSLocale localeWithLocaleIdentifier:dictionary[@"identifier"]];
}- (NSString *)JSONObjectForLocale
{return self.locale.localeIdentifier;
}@end自定义验证JSON
@interface ProductModel : JSONModel
@property (nonatomic) NSInteger id;
@property (nonatomic) NSString *name;
@property (nonatomic) float price;
@property (nonatomic) NSLocale *locale;
@property (nonatomic) NSNumber <Ignore> *minNameLength;
@end@implementation ProductModel- (BOOL)validate:(NSError **)error
{if (![super validate:error])return NO;if (self.name.length < self.minNameLength.integerValue){*error = [NSError errorWithDomain:@"me.mycompany.com" code:1 userInfo:nil];return NO;}return YES;
}@end如果您需要查看详情JSONModel的使用请访问https://github.com/jsonmodel/jsonmodel ，以便下载最新代码进行研究使用。
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