iOS 沙盒目录详解

1、获取程序的Home目录
      NSString  *path = NSHomeDirectory();
      NSLog(@"path:%@",path);
      打印结果：
path:/Users/username/Library/Application Support/iPhone Simulator/5.1/Applications/BAE91297-A4C6-4DDC-A9DA-7B790B36CE7A
   真机上的目录是：
/var/mobile/Applications/3B8EC78A-5EEE-4C2F-B0CB-4C3F02B996D2
   可见，真机上的目录是/var/mobile/Applications/这个目录下的，和模拟器不一样。这个是Home目录，其他的子目录和模拟器一样。


2、获取Document目录
   NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 
   NSString *path = [paths objectAtIndex:0]; 
   NSLog(@"path:%@", path); 
   打印结果： 
  path:/Users/username/Library/Application Support/iPhone Simulator/5.1/Applications/BAE91297-A4C6-4DDC-A9DA-7B790B36CE7A/Documents


3、获取Cache目录
   NSArray *paths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES); 
   NSString *path = [paths objectAtIndex:0]; 
   NSLog(@"path:%@", path); 
   打印结果：
path:/Users/username/Library/Application Support/iPhone Simulator/5.1/Applications/BAE91297-A4C6-4DDC-A9DA-7B790B36CE7A/Library/Caches


4、获取Library目录
   NSArray *paths = NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES); 
   NSString *path = [paths objectAtIndex:0]; 
   NSLog(@"path:%@", path);
   打印结果：
path:/Users/username/Library/Application Support/iPhone Simulator/5.1/Applications/BAE91297-A4C6-4DDC-A9DA-7B790B36CE7A/Library
5、获取Tmp目录
   NSString *path = NSTemporaryDirectory(); 
   NSLog(@"%@", path);
   打印结果：
path:/var/folders/hj/8sgyk0f555l1z_n95p2b2kp00000gn/T/  


6、写入文件
   NSArray  *paths  =  NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);
   NSString *docDir = [paths objectAtIndex:0];
   if(!docDir) {
        NSLog(@"Documents 目录未找到");
   }
   NSArray *array = [[NSArray alloc] initWithObjects:@"内容",@"content",nil];
   NSString *filePath = [docDir stringByAppendingPathComponent:@"testFile.txt"];
   [array writeToFile:filePath atomically:YES];


7、读取文件
   NSArray  *paths  =  NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);
   NSString *docDir = [paths objectAtIndex:0];
   NSString *filePath = [docDir stringByAppendingPathComponent:@"testFile.txt"];
   NSArray *array = [[NSArray alloc] initWithContentsOfFile:filePath];
   NSLog(@"%@",array);