iOS 各种系统文件目录临时，缓存，document,lib,归档，序列化

/**
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);

/**

    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

#import <Foundation/Foundation.h>
@interface Address : NSObject<NSCoding>
{
NSString *country;
NSString *city;
}
@property(nonatomic,copy) NSString *country;
@property(nonatomic,copy) NSString *city;
@end

#import <Foundation/Foundation.h>

@interface Address : NSObject<NSCoding>

{

    NSString *country;

    NSString *city;

}

@property(nonatomic,copy) NSString *country;

@property(nonatomic,copy) NSString *city;

@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

#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

#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

#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

#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

#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

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);

 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：

NSMutableDictionary *dataDictionary = [[NSMutableDictionary alloc] init] ;
[dataDictionary setValue:[NSNumber numberWithInt:222] forKey:@"intNumber"];
[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

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

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

读文件：

NSDictionary *dictionaryFromFile = [NSDictionary dictionaryWithContentsOfFile:@"/Users/zhoumoban/Desktop/test.plist"];
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

NSString *error;
NSData *xmlData = [NSPropertyListSerialization dataFromPropertyList:dataDictionary format:NSPropertyListXMLFormat_v1_0 errorDescription:&error];
if(xmlData) {
NSLog(@"No error creating XML data.");
[xmlData writeToFile:@"/Users/zhoumoban/Desktop/test2.plist" atomically:YES];
} else {
if (error) {
NSLog(@"error:%@", error);
// [error release];
}
}
//读取
NSDictionary *dictionaryFromFile2 = (NSDictionary *)[NSPropertyListSerialization propertyListWithData:[NSData dataWithContentsOfFile:@"/Users/zhoumoban/Desktop/test2.plist"] options:0 format:NULL error:&error];
NSLog(@"＝＝＝%@",[dictionaryFromFile2 objectForKey:@"intNumber"]);