JsonModel的使用

基本使用

initWithDictionary使用

@interface Person : JSONModel

@property (nonatomic, copy)   NSString *name;
@property (nonatomic, copy)   NSString *sex;
@property (nonatomic, assign) NSInteger age;

@end

NSDictionary *dict = @{
                        @"name":@"Jack",
                        @"age":@23,
                        @"gender":@"male",
                      };
 NSError *error;
 Person *person = [[Person alloc] initWithDictionary:dict error:&error];

key值转换

原来字典里的gender这个key变成了sex，这就需要我们定义一个转换的mapper（JSONKeyMapper）：



@implementation Person

+ (JSONKeyMapper *)keyMapper
{
    return [[JSONKeyMapper alloc] initWithModelToJSONDictionary:@{
                                                                  @"gender": @"sex",
                                                                  }];
}

自定义错误

比如，当age对应的数值小于25的时候，打印出Too young!,并阻止模型的转换：


- (BOOL)validate:(NSError **)error
{
    if (![super validate:error])
        return NO;
    
    if (self.age < 25)
    {
        *error = [NSError errorWithDomain:@"Too young!" code:10 userInfo:nil];
        NSError *errorLog = *error;
        NSLog(@"%@",errorLog.domain);
        return NO;
    }
    
    return YES;
}

类型自动匹配


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



#import "JSONModel.h"

@interface CountryModel : JSONModel

@property (assign, nonatomic) int id;
@property (strong, nonatomic) NSString* country;
@property (strong, nonatomic) NSString* dialCode;
@property (assign, nonatomic) BOOL isInEurope;

@end


如果传过来的JSON合法，你所定义的所有的属性都会与该JSON的值想对应，甚至JSONModel会尝试去转换数据为你期望的类型，如上所示:

- 转换id，从字符串转换为int
- 只需要拷贝一下country的值
- 转换diaCode，从number转换为字符串
- 最后一个是将isInEurope转换为BOOL属性
`所以，你所需要做的就是将你的属性定义为期望的类型.`

模型嵌套、模型集合

举个例子，我们让上面的Person对象含有一个数组Friends，它里面的元素是对象Friend，也就是好友信息。若要实现模型的嵌套，我们只需在原来的模型类里增加一个协议Friend：

#import "JSONModel.h"
@protocol Friend;

@interface Friend : JSONModel

@property (nonatomic, copy) NSString *name;
@property (nonatomic, assign) NSInteger age;

@end


@interface Person : JSONModel

@property (nonatomic, copy) NSString *name;
@property (nonatomic, assign) NSInteger age;
@property (nonatomic, copy) NSString *gender;
@property (nonatomic, strong) NSArray<Friend> *friends;//数组，嵌套模型

@end

key映射

服务器返回数据


{
  "order_id": 104,
  "order_details" : [
    {
      "name": "Product#1",
      "price": {
        "usd": 12.95
      }
    }
  ]
}

可以随意改对应的字段，可以随意取对应的数据，很强大

@interface OrderModel : JSONModel
@property (assign, nonatomic) int id;
@property (assign, nonatomic) float price;
@property (strong, nonatomic) NSString* productName;
@end

@implementation OrderModel

+(JSONKeyMapper*)keyMapper
{
  return [[JSONKeyMapper alloc] initWithDictionary:@{
    @"order_id": @"id",
    @"order_details.name": @"productName",
    @"order_details.price.usd": @"price"
  }];
}

设置全局键映射(应用于所有model)


[JSONModel setGlobalKeyMapper:[
    [JSONKeyMapper alloc] initWithDictionary:@{
      @"item_id":@"ID",
      @"item.name": @"itemName"
   }]
];

设置下划线自动转驼峰


{
  "order_id": 104,
  "order_product" : @"Product#1",
  "order_price" : 12.95
}

@interface OrderModel : JSONModel

@property (assign, nonatomic) int orderId;
@property (assign, nonatomic) float orderPrice;
@property (strong, nonatomic) NSString* orderProduct;

@end

@implementation OrderModel

+(JSONKeyMapper*)keyMapper
{
  return [JSONKeyMapper mapperFromUnderscoreCaseToCamelCase];
}

@end

可选属性 (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 (assign, nonatomic) int id;
@property (strong, nonatomic) NSString<Optional>* name;
@property (assign, nonatomic) float price;
@property (strong, nonatomic) NSNumber<Optional>* uuid;
@end

@implementation ProductModel
@end

忽略属性 (就是完全忽略这个属性)


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



@interface ProductModel : JSONModel
@property (assign, nonatomic) int id;
@property (strong, nonatomic) NSString<Ignore>* customProperty;
@end

@implementation ProductModel
@end

设置所有的属性为可选(所有属性值可以为空)


@implementation ProductModel
+(BOOL)propertyIsOptional:(NSString*)propertyName
{
  return YES;
}
@end

使用JSONModel自带的 HTTP 请求


//add extra headers
[[JSONHTTPClient requestHeaders] setValue:@"MySecret" forKey:@"AuthorizationToken"];

//make post, get requests
[JSONHTTPClient postJSONFromURLWithString:@"http://mydomain.com/api"
                                   params:@{@"postParam1":@"value1"}
                               completion:^(id json, JSONModelError *err) {

                                   //check err, process json ...

                               }];

将model转化为字典或者json格式的字符串

ProductModel* pm = [[ProductModel alloc] initWithString:jsonString error:nil];
pm.name = @"Changed Name";

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

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