将Array、Dictionary等集合类的序列化和反序列化

来自：http://blog.prosight.me/index.php/tag/writetofile

Objective-C的集合类序列化到文件中或者从文件中反序列化其实很简单，请看下面的示例 代码：

1.  
2. NSArray *array = [NSArray arrayWithObjects:
3.     @"Hefeweizen", @"IPA", @"Pilsner", @"Stout", nil];
4.  
5. NSDictionary *dictionary = [NSDictionary dictionaryWithObjectsAndKeys:
6.   array, @"array", @"Stout", @"dark", @"Hefeweizen", @"wheat", @"IPA",
7.   @"hoppy", nil];
8.  
9. // 得到documents directory的路径
10. NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,
11.   NSUserDomainMask, YES);
12. if ([paths count] > 0)
13. {
14.   // Array的保存路径
15.   NSString  *arrayPath = [[paths objectAtIndex:0]
16.       stringByAppendingPathComponent:@"array.out"];
17.  
18.   // dictionary的保存路径
19.   NSString  *dictPath = [[paths objectAtIndex:0]
20.       stringByAppendingPathComponent:@"dict.out"];
21.  
22.   // 保存array
23.   [array writeToFile:arrayPath atomically:YES];
24.  
25.   // 保存dictionary
26.   [dictionary writeToFile:dictPath atomically:YES];
27.  
28.   // 从文件中读取回来
29.   NSArray *arrayFromFile = [NSArray arrayWithContentsOfFile:arrayPath];
30.   NSDictionary *dictFromFile = [NSDictionary dictionaryWithContentsOfFile:dictPath];
31.  
32.   for (NSString *element in arrayFromFile)
33.     NSLog(@"Beer: %@", element);
34.  
35.   for (NSString *key in dictFromFile)
36.     NSLog(@"%@ Style: %@", key, [dictionary valueForKey:key]);
37. }
38.  

输出如下：