Objective-C Json 实例详解

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Objective-C Json 实例详解

通过使用NSJSONSerialization 可以Json与Foundation的相互转换。下面具体介绍 Objective-c json 的使用。

Json To Fundation

使用 JSONObjectWithData 可以将 Json 转化为 Foundation。Json的顶层可以是{} 或 []因此可以有 NSDictionary 和 NSArray 两种格式。读取使用 ObjectForKey 返回对应的对象。

复制代码

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NSString* items = @"{"items":["item0","item1","item2"]}";
 
NSData *data= [items dataUsingEncoding:NSUTF8StringEncoding];
 
NSError *error = nil;
 
id jsonObject = [NSJSONSerialization JSONObjectWithData:data 
          options:NSJSONReadingAllowFragments 
          error:&amp;error];
 
if ([jsonObject isKindOfClass:[NSDictionary class]]){
 
  NSDictionary *dictionary = (NSDictionary *)jsonObject;
 
  NSLog(@"Dersialized JSON Dictionary = %@", dictionary);
 
}else if ([jsonObject isKindOfClass:[NSArray class]]){
 
  NSArray *nsArray = (NSArray *)jsonObject;
 
  NSLog(@"Dersialized JSON Array = %@", nsArray);
 
} else {
 
  NSLog(@"An error happened while deserializing the JSON data.");
 
}
 
NSDictionary *dict = (NSDictionary *)jsonObject;
 
NSArray* arr = [dict objectForKey:@"items"];
NSLog(@"list is %@",arr);

Fundation To Json

使用 dataWithJsonObject 可以将 Fundation 转换为 Json。其中 options:NSJSONWritingPrettyPrinted 是分行输出json ,无空格输出使用 option:kNilOptions。

下面这段代码是IOS内购获取商品列表。获取后，将内容添加到Json中。

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NSArray *myProduct = response.products;
NSDictionary *myDict;
NSMutableDictionary *dict = [NSMutableDictionary 
                dictionaryWithCapacity: 4];
 
for(int i = 0;i<myProduct.count;++i)
{
 
  //NSLog(@"----------------------");
  //NSLog(@"Product title: %@" ,[myProduct[i] localizedTitle]);
  //NSLog(@"Product description: %@" ,[myProduct[i] localizedDescription]);
  //NSLog(@"Product price: %@" ,[myProduct[i] price]);
  //NSLog(@"Product id: %@" ,[myProduct[i] productIdentifier]);
 
  myDict = [NSDictionary dictionaryWithObjectsAndKeys:
          [myProduct[i] localizedTitle], @"title",
          [myProduct[i] localizedDescription], @"desc",
          [myProduct[i] price], @"price",
          [myProduct[i] productIdentifier], @"product", nil];
 
  [dict setValue: myDict forKey: [myProduct[i] productIdentifier]];
}
if([NSJSONSerialization isValidJSONObject:dict])
{
  NSError* error;
  NSData *str = [NSJSONSerialization dataWithJSONObject:dict 
            options:kNilOptions error:&error];
  NSLog(@"Result: %@",[[NSString alloc]initWithData:str 
              encoding:NSUTF8StringEncoding]);
}
else
{
  NSLog(@"An error happened while serializing the JSON data.");
}

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NSArray *myProduct = response.products;
NSDictionary *myDict;
NSMutableDictionary *dict = [NSMutableDictionary 
                dictionaryWithCapacity: 4];
 
for(int i = 0;i&lt;myProduct.count;++i)
{
 
  //NSLog(@"----------------------");
  //NSLog(@"Product title: %@" ,[myProduct[i] localizedTitle]);
  //NSLog(@"Product description: %@" ,[myProduct[i] localizedDescription]);
  //NSLog(@"Product price: %@" ,[myProduct[i] price]);
  //NSLog(@"Product id: %@" ,[myProduct[i] productIdentifier]);
 
  myDict = [NSDictionary dictionaryWithObjectsAndKeys:
          [myProduct[i] localizedTitle], @"title",
          [myProduct[i] localizedDescription], @"desc",
          [myProduct[i] price], @"price",
          [myProduct[i] productIdentifier], @"product", nil];
 
  [dict setValue: myDict forKey: [myProduct[i] productIdentifier]];
}
if([NSJSONSerialization isValidJSONObject:dict])
{
  NSError* error;
  NSData *str = [NSJSONSerialization dataWithJSONObject:dict 
            options:kNilOptions error:&amp;error];
  NSLog(@"Result: %@",[[NSString alloc]initWithData:str 
              encoding:NSUTF8StringEncoding]);
}
else
{
  NSLog(@"An error happened while serializing the JSON data.");
}