IOS 沙盒机制 浅析

IOS中的沙盒机制（SandBox）是一种安全体系，它规定了应用程序只能在为该应用创建的文件夹内读取文件，不可以访问其他地方的内容。所有的非代码文件都保存在这个地方，比如图片、声音、属性列表和文本文件等。

2.不能随意跨越自己的沙盒去访问别的应用程序沙盒的内容

3.应用程序向外请求或接收数据都需要经过权限认证

//获取home目录
    NSString *homePath = NSHomeDirectory();
    NSLog(@"home%@",homePath);
   
    //获取documents目录
    //方式1：
    NSArray *documents = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsPath = [documents lastObject];
    NSLog(@"%@",documentsPath);
    //方式2：拼接字符串
    NSString *documentPath2 = [homePath stringByAppendingPathComponent:@"Documents"];
    NSLog(@"documenPath2:%@",documentPath2);
   
    //获取caches缓存目录
    NSArray *caches = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
    NSString *cachesPath = [caches lastObject];
    NSLog(@"cachesPath:%@",cachesPath);
   
    //获取临时目录
    NSString *tmp = NSTemporaryDirectory();
    NSLog(@"tmp:%@",tmp);
   
    //在documents目录下创建文件
    NSFileManager *fm = [NSFileManager defaultManager];
    NSString *fileName = [documentsPath stringByAppendingPathComponent:@"1.txt"];
    NSString *str = @"hello world";
    NSData *data = [str dataUsingEncoding:NSUTF8StringEncoding];
   
    if ([fm createFileAtPath:fileName contents:data attributes:nil]) {
        NSLog(@"file create successful");
    }
   
    //读出文件的内容
    NSError *error = nil;
   
    NSString *str2 = [NSString stringWithContentsOfFile:fileName encoding:NSUTF8StringEncoding error:&error];
    if (!error) {
        NSLog(@"str2:%@",str2);
    }
    else
    {
        NSLog(@"%@",error);
    }
    //NSBundle对象：图片、xib、storyBoard、plist文件都是放在应用程序包中
    NSBundle *bundle = [NSBundle mainBundle];
    //获取包中文件的路径；
    NSString *path = [bundle pathForResource:@"array" ofType:@"plist"];
    //加载包中的xib文件
    NSArray *views  = [bundle loadNibNamed:@"cell" owner:self options:nil];

NSUserDefaults *userDeafults = [NSUserDefaults standardUserDefaults];
   
    [userDeafults setObject:@"admin" forKey:@"userName"];
    [userDeafults setObject:[NSDate date] forKey:@"loginDate"];
    [userDeafults setInteger:2 forKey:@"loginTimes"];
   
    //将偏好设置写到文件中去
    [userDeafults synchronize];//同步方法
   
    //获取home目录
    NSString *homePath = NSHomeDirectory();
    NSLog(@"%@",homePath);
 
 NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
    NSString *userName = [userDefaults objectForKey:@"userName"];
    NSDate *loginDate = [userDefaults objectForKey:@"loginDate"];
    NSString *loginTimes = [userDefaults objectForKey:@"loginTimes"];
    NSLog(@"%@,%@",userName,loginTimes);
    NSDateFormatter *df = [[NSDateFormatter alloc]init];
    df.dateFormat = @"MM-dd HH-mm-ss";
    NSLog(@"loginDate:%@",[df stringFromDate:loginDate]);

三、应用沙盒结构分析