如何将 NSDictionary 转换为自定义对象

我有一个 json 对象：

@interface Order : NSObject

@property (nonatomic, retain) NSString *OrderId;
@property (nonatomic, retain) NSString *Title;
@property (nonatomic, retain) NSString *Weight;

- (NSMutableDictionary *)toNSDictionary;
...

- (NSMutableDictionary *)toNSDictionary
{

    NSMutableDictionary *dictionary = [[NSMutableDictionary alloc] init];
    [dictionary setValue:self.OrderId forKey:@"OrderId"];
    [dictionary setValue:self.Title forKey:@"Title"];
    [dictionary setValue:self.Weight forKey:@"Weight"];

    return dictionary;
}

在字符串中是：

{
  "Title" : "test",
  "Weight" : "32",
  "OrderId" : "55"
}

我用代码获取字符串 JSON：

NSMutableDictionary* str = [o toNSDictionary];

    NSError *writeError = nil;

    NSData *jsonData = [NSJSONSerialization dataWithJSONObject:str options:NSJSONWritingPrettyPrinted error:&writeError];
    NSString *jsonString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];

现在我需要从 JSON 字符串创建并映射对象:

NSData *jsonData = [jsonString dataUsingEncoding:NSUTF8StringEncoding];
    NSError *e;
    NSDictionary *dict = [NSJSONSerialization JSONObjectWithData:jsonData options:nil error:&e];

这会返回我填充的 ​​NSDictionary。 我应该怎么做才能从这本字典中获取对象？

添加新的initWithDictionary:方法Order:

- (instancetype)initWithDictionary:(NSDictionary*)dictionary {
    if (self = [super init]) {
        self.OrderId = dictionary[@"OrderId"];
        self.Title = dictionary[@"Title"];
        self.Weight = dictionary[@"Weight"];    
    }
    return self;    
}

不要忘记添加initWithDictionary的签名Order.h file

在获取 JSON 的方法中：

NSData *jsonData = [jsonString dataUsingEncoding:NSUTF8StringEncoding];
NSError *e;
NSDictionary *dict = [NSJSONSerialization JSONObjectWithData:jsonData options:nil error:&e];
Order *order = [[Order alloc] initWithDictionary:dict];