数据存储之沙盒

一、沙盒

每个IOS程序都有自己的程序目录(沙盒),与其他系统文件隔离，应用只能访问自己的沙盒(IOS8中已经开放)

应⽤沙盒的文件系统⽬录,如下图所示(假设应用的名称叫Layer)

模拟器应⽤用沙盒的根路径在: (city--online是⽤用户名)

/Users/city--online/Library/Developer/CoreSimulator/Devices/18B16F4E-BB49-41F1-90AE-842283E72C8C/data/Containers/Data/Application/D81121AC-377F-487B-A844-AC3A313D495C

Documents:保存应⽤运行时生成的需要持久化的数据,iTunes同步设备时会备份该目录。例如,游戏应用可将游戏存档保存在该目录

tmp:保存应⽤运行时所需的临时数据,使⽤完毕后再将相应的文件从该目录删除。应用没有运行时,系统也可能会清除该目录下的文件。iTunes同步设备时 不会备份该目录

Library/Caches:保存应用运行时⽣成的需要持久化的数据,iTunes同步设备时不会备份该目录。⼀一般存储体积大、不需要备份的非重要数据

Library/Preference:保存应用的所有偏好设置,iOS的Settings(设置) 应⽤会在该⺫录中查找应⽤的设置信息。iTunes同步设备时会备份该目录 

//
//  ViewController.m
//  Plist
//
//  Created by City--Online on 15/4/21.
//  Copyright (c) 2015年 CYW. All rights reserved.
//

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    //获取沙盒根目录
    NSString *home=NSHomeDirectory();
     NSLog(@"沙盒根目录:%@\n\n",home);

    //获取Documents目录 不建议采用
    NSString *documents=[home stringByAppendingPathComponent:@"Documents"];
    NSLog(@"字符串拼接获取Documents:%@\n\n",documents);

    //NSUserDomainMask 代表从用户文件夹下找
    //YES  代表展开路径中的波浪字符“~” NO ~/Documents
    NSArray *array=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, NO);
    // 在iOS中,只有一个目录跟传入的参数匹配,所以这个集合里面只有一个元素
    NSString *documents1=[array objectAtIndex:0];
    NSLog(@"通过方法NSSearchPathForDirectoriesInDomains获取Documents:%@\n\n",documents1);

    //获取tmp文件目录
    NSLog(@"tmp 文件目录:%@\n\n",NSTemporaryDirectory());

    //获取Library/Caches:
    NSArray *arrayCaches=NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
    NSLog(@"Library/Caches:%@",arrayCaches[0]);

    //Library/Preference:通过NSUserDefaults类存取该目录下的设置信息

}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end

 输出:

2015-04-21 13:44:39.565 Plist[2829:130133] 沙盒根目录:/Users/city--online/Library/Developer/CoreSimulator/Devices/18B16F4E-BB49-41F1-90AE-842283E72C8C/data/Containers/Data/Application/1F25A9BC-BB1D-4F5D-88F1-A96E9E0E9EAE

2015-04-21 13:44:39.566 Plist[2829:130133] 字符串拼接获取Documents:/Users/city--online/Library/Developer/CoreSimulator/Devices/18B16F4E-BB49-41F1-90AE-842283E72C8C/data/Containers/Data/Application/1F25A9BC-BB1D-4F5D-88F1-A96E9E0E9EAE/Documents

2015-04-21 13:44:39.566 Plist[2829:130133] 通过方法NSSearchPathForDirectoriesInDomains获取Documents:~/Documents

2015-04-21 13:44:39.566 Plist[2829:130133] tmp 文件目录:/Users/city--online/Library/Developer/CoreSimulator/Devices/18B16F4E-BB49-41F1-90AE-842283E72C8C/data/Containers/Data/Application/1F25A9BC-BB1D-4F5D-88F1-A96E9E0E9EAE/tmp/

2015-04-21 13:44:39.567 Plist[2829:130133] Library/Caches:/Users/city--online/Library/Developer/CoreSimulator/Devices/18B16F4E-BB49-41F1-90AE-842283E72C8C/data/Containers/Data/Application/1F25A9BC-BB1D-4F5D-88F1-A96E9E0E9EAE/Library/Caches