iOS 各种系统文件目录 临时，缓存，document,lib,归档，序列化

1. /**
2. 1:Documents：应用中用户数据可以放在这里，iTunes备份和恢复的时候会包括此目录
3. 2:tmp：存放临时文件，iTunes不会备份和恢复此目录，此目录下文件可能会在应用退出后删除
4. 3:Library/Caches：存放缓存文件，iTunes不会备份此目录，此目录下文件不会在应用退出删除
5. */
6. NSArray *paths1=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory
7. , NSUserDomainMask
8. , YES);
9. NSString *documentsDirect=[paths1 objectAtIndex:0];
10. assert(1 == paths1.count);
11. NSLog(@">>documentsDirect=%@",documentsDirect);
12. NSArray *Librarypaths =  NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory, NSDocumentDirectory, YES);
13. NSString* libraryDirectory  = [Librarypaths objectAtIndex:0];
14. NSLog(@">>Librarypaths.length =%d",[Librarypaths count]);
15. assert(1 < Librarypaths.count);
16. NSLog(@"libraryDirectory=%@",libraryDirectory);
17. //如果要指定其他文件目录，比如Caches目录，需要更换目录工厂常量，上面代码其他的可不变
18. NSArray *pathcaches=NSSearchPathForDirectoriesInDomains(NSCachesDirectory
19. , NSUserDomainMask
20. , YES);
21. NSString* cacheDirectory  = [pathcaches objectAtIndex:0];
22. NSLog(@"cacheDirectory=%@",cacheDirectory);
23. /**
24. 使用NSSearchPathForDirectoriesInDomains只能定位Caches目录和Documents目录。
25. tmp目录，不能按照上面的做法获得目录了，有个函数可以获得应用的根目录
26. */
27. NSString *tempDir1=NSHomeDirectory() ;
28. NSString *tempDir2=NSTemporaryDirectory();
29. NSLog(@"tempDir1=%@",tempDir1);
30. NSLog(@"tempDir2=%@",tempDir2);

/**
    1:Documents：应用中用户数据可以放在这里，iTunes备份和恢复的时候会包括此目录
    2:tmp：存放临时文件，iTunes不会备份和恢复此目录，此目录下文件可能会在应用退出后删除
    3:Library/Caches：存放缓存文件，iTunes不会备份此目录，此目录下文件不会在应用退出删除
     */
    NSArray *paths1=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory
                                                       , NSUserDomainMask
                                                       , YES);

    NSString *documentsDirect=[paths1 objectAtIndex:0];
    assert(1 == paths1.count);
    NSLog(@">>documentsDirect=%@",documentsDirect);

    NSArray *Librarypaths =  NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory, NSDocumentDirectory, YES);
    NSString* libraryDirectory  = [Librarypaths objectAtIndex:0];
    NSLog(@">>Librarypaths.length =%d",[Librarypaths count]);
     assert(1 < Librarypaths.count);

    NSLog(@"libraryDirectory=%@",libraryDirectory);

    //如果要指定其他文件目录，比如Caches目录，需要更换目录工厂常量，上面代码其他的可不变
    NSArray *pathcaches=NSSearchPathForDirectoriesInDomains(NSCachesDirectory
                                                       , NSUserDomainMask
                                                       , YES);
    NSString* cacheDirectory  = [pathcaches objectAtIndex:0];
    NSLog(@"cacheDirectory=%@",cacheDirectory);
    /**
     使用NSSearchPathForDirectoriesInDomains只能定位Caches目录和Documents目录。

     tmp目录，不能按照上面的做法获得目录了，有个函数可以获得应用的根目录
     */
    NSString *tempDir1=NSHomeDirectory() ;
    NSString *tempDir2=NSTemporaryDirectory();
    NSLog(@"tempDir1=%@",tempDir1);
    NSLog(@"tempDir2=%@",tempDir2);

归档 普通自定义对象和字节流之间的转换

 序列化 某些特定类型（NSDictionary, NSArray, NSString, NSDate, NSNumber，NSData）的数据和字节流之间(通常将其保存为plist文件)的转换

2.1 归档

如果我们需要将自定义的一个对象保存到文件，应该如何做呢？

这里引入两个东西：一个是NSCoding协议 ；另一个是NSKeyedArchiver，NSKeyedArchiver其实继承于NSCoder，可以以键值对的方式将对象的属性进行序列化和反序列化。 
具体的过程可以这样描述 通过NSKeyedArchiver 可以将实现了NSCoding协议的对象 和 字节流 相互转换 。

像一些框架中的数据类型如NSDictionary,NSArray,NSString... 都已经实现了NSCoding协议，所以可以直接对他们进行归档操作。

这里来一个比较完整的例子，一个Address类，一个User类，User类下有个Address类型的属性

1. #import <Foundation/Foundation.h>
2. @interface Address : NSObject<NSCoding>
3. {
4. NSString *country;
5. NSString *city;
6. }
7. @property(nonatomic,copy) NSString *country;
8. @property(nonatomic,copy) NSString *city;
9. @end

#import <Foundation/Foundation.h>

@interface Address : NSObject<NSCoding>
{
    NSString *country;
    NSString *city;
}
@property(nonatomic,copy) NSString *country;
@property(nonatomic,copy) NSString *city;
@end

1. #import "Address.h"
2. @implementation Address
3. @synthesize country;
4. @synthesize city;
5. - (void)encodeWithCoder:(NSCoder *)aCoder{
6. [aCoder encodeObject:country forKey:@"country"];
7. [aCoder encodeObject:city forKey:@"city"];
8. }
9. - (id)initWithCoder:(NSCoder *)aDecoder{
10. if (self = [super init]) {
11. [self setCountry:[aDecoder decodeObjectForKey:@"country"]];
12. [self setCity:[aDecoder decodeObjectForKey:@"city"]];
13. } return self;
14. }
15. @end

#import "Address.h"

@implementation Address
@synthesize country;
@synthesize city;
- (void)encodeWithCoder:(NSCoder *)aCoder{
    [aCoder encodeObject:country forKey:@"country"];
    [aCoder encodeObject:city forKey:@"city"];
}
- (id)initWithCoder:(NSCoder *)aDecoder{
    if (self = [super init]) {
        [self setCountry:[aDecoder decodeObjectForKey:@"country"]];
        [self setCity:[aDecoder decodeObjectForKey:@"city"]];
    } return self;
}
@end

1. #import <Foundation/Foundation.h>
2. #import "Address.h"
3. @interface User : NSObject<NSCoding>{
4. NSString *_name;
5. NSString *_password;
6. Address *_address;
7. }
8. @property(nonatomic,copy) NSString *name;
9. @property(nonatomic,copy) NSString *password;
10. @property(nonatomic,retain) Address *address;
11. @end

#import <Foundation/Foundation.h>
#import "Address.h"
@interface User : NSObject<NSCoding>{
    NSString *_name;
    NSString *_password;
    Address *_address;
}
@property(nonatomic,copy) NSString *name;
@property(nonatomic,copy) NSString *password;
@property(nonatomic,retain) Address *address;

@end

1. #import "User.h"
2. @implementation User
3. @synthesize name = _name;
4. @synthesize password = _password;
5. @synthesize address = _address;
6. - (void)encodeWithCoder:(NSCoder *)aCoder{
7. [aCoder encodeObject:_name forKey:@"name"];
8. [aCoder encodeObject:_password forKey:@"password"];
9. [aCoder encodeObject:_address forKey:@"address"];
10. }
11. - (id)initWithCoder:(NSCoder *)aDecoder{
12. if (self = [super init]) {
13. [self setName:[aDecoder decodeObjectForKey:@"name"]];
14. [self setPassword:[aDecoder decodeObjectForKey:@"password"]];
15. [self setAddress:[aDecoder decodeObjectForKey:@"address"]];
16. }
17. return self;
18. }
19. @end

#import "User.h"

@implementation User
@synthesize name = _name;
@synthesize password = _password;
@synthesize address = _address;

- (void)encodeWithCoder:(NSCoder *)aCoder{
    [aCoder encodeObject:_name forKey:@"name"];
    [aCoder encodeObject:_password forKey:@"password"];
    [aCoder encodeObject:_address forKey:@"address"];
}
- (id)initWithCoder:(NSCoder *)aDecoder{
    if (self = [super init]) {
        [self setName:[aDecoder decodeObjectForKey:@"name"]];
        [self setPassword:[aDecoder decodeObjectForKey:@"password"]];
        [self setAddress:[aDecoder decodeObjectForKey:@"address"]];
    }
    return self;
}

@end

操作应用

1. NSString *tempDir2=NSTemporaryDirectory();
2. // Do any additional setup after loading the view, typically from a nib.
3. Address *myAddress = [[Address alloc] init] ;
4. myAddress.country = @"中国";
5. myAddress.city = @"杭州";
6. User *user = [[User alloc] init] ;
7. user.name = @"卢克";
8. user.password = @"lukejin";
9. user.address = myAddress;
10. //归档  保存的是plist的二进制数据格式
11. NSString *path = [tempDir2 stringByAppendingPathComponent:@"user"];
12. [NSKeyedArchiver archiveRootObject:user toFile:path];
13. //从文档中读取
14. User *object = [NSKeyedUnarchiver unarchiveObjectWithFile:path];
15. NSLog(@"object.name : %@",object.name);

 NSString *tempDir2=NSTemporaryDirectory();    

	// Do any additional setup after loading the view, typically from a nib.
    Address *myAddress = [[Address alloc] init] ;
    myAddress.country = @"中国";
    myAddress.city = @"杭州";
    User *user = [[User alloc] init] ;

    user.name = @"卢克";
    user.password = @"lukejin";
    user.address = myAddress;
    //归档  保存的是plist的二进制数据格式
    NSString *path = [tempDir2 stringByAppendingPathComponent:@"user"];
    [NSKeyedArchiver archiveRootObject:user toFile:path];

    //从文档中读取
    User *object = [NSKeyedUnarchiver unarchiveObjectWithFile:path];
    NSLog(@"object.name : %@",object.name);

使用数据对象自带的方法，如字典类写文件：

数据：

1. NSMutableDictionary *dataDictionary = [[NSMutableDictionary alloc] init] ;
2. [dataDictionary setValue:[NSNumber numberWithInt:222] forKey:@"intNumber"];
3. [dataDictionary setValue:[NSArray arrayWithObjects:@"1",@"2", nil] forKey:@"testArray"];

  NSMutableDictionary *dataDictionary = [[NSMutableDictionary alloc] init] ;
    [dataDictionary setValue:[NSNumber numberWithInt:222] forKey:@"intNumber"];
    [dataDictionary setValue:[NSArray arrayWithObjects:@"1",@"2", nil] forKey:@"testArray"];

写文件

1. [dataDictionary writeToFile:@"/Users/zhoumoban/Desktop/test.plist" atomically:YES];

[dataDictionary writeToFile:@"/Users/zhoumoban/Desktop/test.plist" atomically:YES];

读文件：

1. NSDictionary *dictionaryFromFile = [NSDictionary dictionaryWithContentsOfFile:@"/Users/zhoumoban/Desktop/test.plist"];
2. NSLog(@"%@",[dictionaryFromFile objectForKey:@"intNumber"]);

 NSDictionary *dictionaryFromFile = [NSDictionary dictionaryWithContentsOfFile:@"/Users/zhoumoban/Desktop/test.plist"];
    NSLog(@"%@",[dictionaryFromFile objectForKey:@"intNumber"]);

另外：使用NSPropertyListSerialization类。通过NSPropertyListSerialization类可以将数据对象直接转成NSData或者直接写到文件或者流中去

1. NSString *error;
2. NSData *xmlData = [NSPropertyListSerialization dataFromPropertyList:dataDictionary format:NSPropertyListXMLFormat_v1_0 errorDescription:&error];
3. if(xmlData) {
4. NSLog(@"No error creating XML data.");
5. [xmlData writeToFile:@"/Users/zhoumoban/Desktop/test2.plist" atomically:YES];
6. } else {
7. if (error) {
8. NSLog(@"error:%@", error);
9. // [error release];
10. }
11. }
12. //读取
13. NSDictionary *dictionaryFromFile2 = (NSDictionary *)[NSPropertyListSerialization propertyListWithData:[NSData dataWithContentsOfFile:@"/Users/zhoumoban/Desktop/test2.plist"] options:0 format:NULL error:&error];
14. NSLog(@"＝＝＝%@",[dictionaryFromFile2 objectForKey:@"intNumber"]);