NSJSONSerialization解析JSON数据

 1 - (IBAction)touchReadButton:(id)sender { 
 2       NSData *jsonData = [[NSData alloc] initWithContentsOfFile:JSON_PATH];     /* Now try to deserialize the JSON object into a dictionary */
 3       NSError *error = nil;
 4       id jsonObject = [NSJSONSerialization JSONObjectWithData:jsonData options:NSJSONReadingAllowFragments error:&error];
 5      if (jsonObject != nil && error == nil){
 6          NSLog(@"Successfully deserialized...");
 7          if ([jsonObject isKindOfClass:[NSDictionary class]]){
 8               NSDictionary *deserializedDictionary = (NSDictionary *)jsonObject;
 9               NSLog(@"Dersialized JSON Dictionary = %@",deserializedDictionary);
10          } else if ([jsonObject isKindOfClass:[NSArray class]]){
11              NSArray *deserializedArray = (NSArray *)jsonObject;
12              NSLog(@"Dersialized JSON Array = %@",deserializedArray);
13          } else {
14              NSLog(@"An error happened while deserializing the JSON data.");
15          }
16      }
17      [jsonData release];
18  }

  
  

   
   
NSJSONSerialization介绍
  
  
  
  

   
   　ios5中apple增加了解析JSON的api——NSJSONSerialization。网上已经有人做过测试，NSJSONSerialization在效率上完胜SBJSON、TouchJSON、YAJL、JSONKit、NextiveJson。
   
   详情见这里
   
   。既然apple为我们提供了这么良好的工具，我们没理由不用吧。
  
  
  
  

   
   
　　NSJSONSerialization提供了将JSON数据转换为Foundation对象（一般都是NSDictionary和NSArray）和Foundation对象转换为JSON数据（可以通过调用isValidJSONObject来判断Foundation对象是否可以转换为JSON数据）。
   
   
　　下面提供一个从豆瓣电台下载的json数据转换的代码
   
   

   
   
#define kGlobalQueue    dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT,0)
#define kDoubanUrl      @"http://douban.fm/j/mine/playlist?type=n&h=&channel=0&from=mainsite&r=4941e23d79"
-(void) loadJsonData:(NSURL *)url
{
    dispatch_async(kGlobalQueue,^{
        NSData *data = [NSData dataWithContentsOfURL:url];
        [self performSelectorOnMainThread:@selector(parseJsonData:) withObject:data waitUntilDone:NO];
    });
}
-(void) parseJsonData:(NSData *)data
{
    NSError *error;
    NSDictionary *json = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error];
    if (json == nil) {
        NSLog(@"json parse failed rn");
        return;
    }
    NSArray *songArray = [json objectForKey:@"song"];
    NSLog(@"song collection: %@rn",songArray);

    _song = songArray;
    self.songIndex = 0;
    NSDictionary *song = [songArray objectAtIndex:0];
    NSLog(@"song info: %@tn",song);
}
   
   
NSDictionary *song = [NSDictionary dictionaryWithObjectsAndKeys:@"i can fly",@"title",@"4012",@"length",@"Tom",@"Singer",nil];
    if ([NSJSONSerialization isValidJSONObject:song])
    {
        NSError *error;
        NSData *jsonData = [NSJSONSerialization dataWithJSONObject:song options:NSJSONWritingPrettyPrinted error:&error];
        NSString *json =[[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
        NSLog(@"json data:%@",json);
    }
   
   
 
    
 
   
   
   
   
   
iOS5.0新功能之——NSJSONSerialization解析JSON数据
   
   

   
   
   
   

   
   


   
   
   
   

   
   
iOS5.0新功能之——NSJSONSerialization解析JSON数据
- (IBAction)touchWriteButton:(id)sender {
 NSMutableDictionary *dictionary = [[NSMutableDictionary alloc] init];
 [dictionary setValue:@"Anthony" forKey:@"First Name"];
 [dictionary setValue:@"Robbins" forKey:@"Last Name"];
 [dictionary setValue:[NSNumber numberWithUnsignedInteger:51] forKey:@"Age"];
 NSArray *arrayOfAnthonysChildren = [[NSArray alloc] initWithObjects:@"Anthony's Son 1",@"Anthony's Daughter 1",@"Anthony's Son 2",@"Anthony's Son 3",@"Anthony's Daughter 2",nil];
 [dictionary setValue:arrayOfAnthonysChildren forKey:@"children"];
 NSError *error = nil;
 NSData *jsonData = [NSJSONSerialization dataWithJSONObject:dictionary options:NSJSONWritingPrettyPrinted error:&error];
 if (error) {
 NSLog(@"dic->%@",error);
 }
 [dictionary release];
 BOOL succeed = [jsonData writeToFile:JSON_PATH atomically:YES];
 if (succeed) {
 NSLog(@"Save succeed");
 }else {
 NSLog(@"Save fail");
 }
}
- (IBAction)touchReadButton:(id)sender { NSData *jsonData = [[NSData alloc] initWithContentsOfFile:JSON_PATH]; /* Now try to deserialize the JSON object into a dictionary */ NSError *error = nil; id jsonObject = [NSJSONSerialization JSONObjectWithData:jsonData options:NSJSONReadingAllowFragments error:&error]; if (jsonObject != nil && error == nil){ NSLog(@"Successfully deserialized..."); if ([jsonObject isKindOfClass:[NSDictionary class]]){ NSDictionary *deserializedDictionary = (NSDictionary *)jsonObject; NSLog(@"Dersialized JSON Dictionary = %@",deserializedDictionary); } else if ([jsonObject isKindOfClass:[NSArray class]]){ NSArray *deserializedArray = (NSArray *)jsonObject; NSLog(@"Dersialized JSON Array = %@",deserializedArray); } else { NSLog(@"An error happened while deserializing the JSON data."); } } [jsonData release]; }