JSONKit是Object-C一个处理json数据的库，非常高效而且易用，对比同类型的库有非常明显的性能优势，见下图：
JSON和Object-C中数据类型的映射关系如下表所示
| JSON | Objective-C |
|---|---|
null |
NSNull |
true false |
NSNumber |
| Number |
NSNumber |
| String |
NSString |
| Array |
NSArray |
| Object |
NSDictionary |
下面写一个简单的程序使用一下JSONKit（只需下载头文件以及源文件，放在项目目录下）
[cpp] view plaincopy
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#import
-
#import
"lib/JSONKit.h" -
-
int
main int( argc, constchar * argv[]) { -
NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init]; -
-
NSString *res = nil; -
-
-
-
//字符串 -
NSString *str = @"this is ;a nsstring" -
res = [str JSONString]; -
NSLog(@"res= %@" ,[NSString stringWithString: res]); -
//res= "this is a nsstring" -
-
-
//数组 -
NSArray *arr = [[NSArray alloc] initWithObjects:@"One",@"Two",@"Three",nil]; -
res = [arr JSONString]; -
NSLog(@"res= %@" ,[NSString stringWithString: res]); -
[arr release]; -
//res= ["One","Two","Three"] -
-
-
//字典类型（对象） -
NSArray *arr1 = [NSArray arrayWithObjects:@"dog",@"cat",nil]; -
NSArray *arr2 = [NSArray arrayWithObjects:[NSNumber numberWithBool:YES],[NSNumber numberWithInt:30],nil]; -
NSDictionary *dic = [NSDictionary dictionaryWithObjectsAnd Keys:arr1,@"pets",arr2,@"other",nil]; -
res = [dic JSONString]; -
NSLog(@"res= %@" ,[NSString stringWithString: res]); -
//res= {"pets":["dog","cat"],"other":[true,30]} -
-
-
-
JSONDecoder *jd=[[JSONDecoder alloc] init]; -
-
//针对NSData数据 -
NSData *data = [dic JSONData]; -
NSDictionary *ret = [jd objectWithData: data]; -
NSLog(@"res= %@" ,[ret "pets"]);objectForKey:@ -
//res= ( -
// dog, -
// cat -
//) -
NSLog(@"res= %@" ,[[ret "other"]objectForKey:@ objectAtIndex:0]); -
//res= 1 -
-
//针对NSString字符串数据 -
NSString *nstr = [dic JSONString]; -
NSDictionary *ret2 = [jd objectWithUTF8String:(const unsigned char*)[nstr int)[nstrUTF8String] length:(unsigned length]]; -
NSLog(@"res= %d" ,[[ret2 "pets"]objectForKey:@ indexOfObject:@ "cat"]); -
//res= 1 -
NSLog(@"res= %@" ,[[ret2 "other"]objectForKey:@ objectAtIndex:1]); -
//res= 30 -
-
[jd release]; -
-
[pool drain]; -
return 0; -
}
JSONKit的接口中还可以自行定制序列化和反序列化选项，针对如何提升效率作者也是给了很多使用的建议，例如尽量使用NSData来替换NSString类型，因为JSON数据通常是用来通信使用，而通信过程使用NSData类型更为高效，毕竟是二进制流数据更短，所以没必要转成NSString多此一举了。不知道我理解得对不对。