JSONModel

一、引入

1、CocoaPods

pod 'JSONModel'

2、Carthage

github "jsonmodel/jsonmodel"

3、手动导入

• 下载JSONModel仓库
• 把JSONModel下的文件导入到你的工程
• 将SystemConfiguration.framework链接到你的应用程序中

二、用法

1、基本用法

假设说你有个这个样子的JSON

{ "id": 10, "country": "Germany", "dialCode": 49, "isInEurope": true }

• 首先为你的数据模型建一个JSON的子类
• 在你数据模型的头文件里，用JSON的key值作为属性的名字

@interface CountryModel : JSONModel
@property (nonatomic) NSInteger id;
@property (nonatomic) NSString *country;
@property (nonatomic) NSString *dialCode;
@property (nonatomic) BOOL isInEurope;
@end

你不需要在.m文件里写任何东西

• 用数据实例化你的模型类

NSError *error;
CountryModel *country = [[CountryModel alloc] initWithString:myJson error:&error];

如果JSON的验证通过。您的模型中包含所有相应的属性，从JSON中填充。JSONModel还将尝试将尽可能多的数据转换为您期望的类型。在上面的例子中，它将：

• 转换id从字符串（以JSON）到int你的类
• 复制该country值
• 将dialCode数字（在JSON中）转换为NSString值
• 复制该isInEurope值

三、示例

1、自动名称映射

{
    "id": 123,
    "name": "Product name",
    "price": 12.95
}
@interface ProductModel : JSONModel
@property (nonatomic) NSInteger id;
@property (nonatomic) NSString *name;
@property (nonatomic) float price;
@end

2、模型嵌套（模型包含其它模型）

{
    "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

3、模型集合

{
    "orderId": 104,
    "totalPrice": 103.45,
    "products": [
        {
            "id": 123,
            "name": "Product #1",
            "price": 12.95
        },
        {
            "id": 137,
            "name": "Product #2",
            "price": 82.95
        }
    ]
}

@class ProductModel;
@protocol ProductModel <NSObject>
@end

@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

注意：NSArray后的<>包含一个协议。这与OC泛型系统不同。它们不是相互排斥的，但是对于JSONModel来说，协议必须到位。

4、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

5、映射到snake_case（去掉中间的下划线）

{
    "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

6、可选属性（即可以缺少或为null）

{
    "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

7、被忽略的属性（即JSONModel完全忽略它们）

{
    "id": 123,
    "name": null
}

@interface ProductModel : JSONModel
@property (nonatomic) NSInteger id;
@property (nonatomic) NSString <Ignore> *customProperty;
@end

8、使标量类型可选

{
    "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

9、将模型导出为NSDictionary或JSON

ProductModel *pm = [ProductModel new];
pm.name = @"Some Name";

// convert to dictionary
NSDictionary *dict = [pm toDictionary];

// convert to json
NSString *string = [pm toJSONString];

10、自定义数据转换

@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

11、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

12、自定义JSON验证

@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