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 \r\n"); return; } NSArray *songArray = [json objectForKey:@"song"]; NSLog(@"song collection: %@\r\n",songArray); _song = songArray; self.songIndex = 0; NSDictionary *song = [songArray objectAtIndex:0]; NSLog(@"song info: %@\t\n",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
- (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];
}