文件操作常用操作記錄一下：

 //獲取沙盒的根路徑
    NSString *dirHome = NSHomeDirectory();
    NSLog(@%@,dirHome);
    //獲取Documents目錄路徑
    NSArray *path = NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory,NSUserDomainMask, YES);
    NSString *documentsDirectory = [path objectAtIndex:0];
    NSLog(@%@,documentsDirectory);
    //獲取Library 目錄路徑
    path = NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES);
    NSString *libraryDirectory  = [path objectAtIndex:0];
    NSLog(@%@,libraryDirectory);
    //獲取caches目錄路徑
    path = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
    NSString *caches = [path objectAtIndex:0];
    NSLog(@%@,caches);
    //獲取Tmp 目錄路徑
    NSString *tmpDirectory = NSTemporaryDirectory();
    NSLog(@%@,tmpDirectory);
    //創建文件夾
    //1 獲得文件路徑
    //2 創建文件管理器
    //3 用文件管理器在目錄上創建文件
    path = NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory,NSUserDomainMask, YES);
    documentsDirectory = [path objectAtIndex:0];
    documentsDirectory = [documentsDirectory stringByAppendingPathComponent:@test];
    NSFileManager *fm = [NSFileManager defaultManager];
    BOOL res = [fm createDirectoryAtPath:documentsDirectory withIntermediateDirectories:YES attributes:nil error:nil];
    if(!res)
    {
        NSLog(@文件夾創建成功);
    }
    else
    {
        NSLog(@文件夾創建失敗);
    }
    //創建文件（與文件夾的創建相同）
    path = NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory, NSUserDomainMask, YES);
    documentsDirectory = [path objectAtIndex:0];
    documentsDirectory = [documentsDirectory stringByAppendingPathComponent:@text];
    documentsDirectory = [documentsDirectory stringByAppendingPathComponent:@123.txt];
    fm = [NSFileManager defaultManager];
    res = [fm createDirectoryAtPath:documentsDirectory withIntermediateDirectories:YES attributes:nil error:nil];
    if(res)
    {
        NSLog(@文件夾創建成功);
    }
    else
    {
        NSLog(@文件夾創建失敗);
    }
    //寫數據到文件
    path = NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory, NSUserDomainMask, YES);
    documentsDirectory = [path objectAtIndex:0];
    documentsDirectory = [documentsDirectory stringByAppendingPathComponent:@text];
    documentsDirectory = [documentsDirectory stringByAppendingPathComponent:@123.txt];
    NSString *content = @文件寫入的內容;
    res = [content writeToFile:documentsDirectory atomically:YES encoding:NSUTF8StringEncoding error:nil];
    if(res)
    {
        NSLog(@文件夾創建成功);
    }
    else
    {
        NSLog(@文件夾創建失敗);
    }
    //讀文件數據
    path = NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory, NSUserDomainMask, YES);
    documentsDirectory = [path objectAtIndex:0];
    documentsDirectory = [documentsDirectory stringByAppendingPathComponent:@text];
    documentsDirectory = [documentsDirectory stringByAppendingPathComponent:@123.txt];
    content  = [NSString stringWithContentsOfFile:documentsDirectory encoding:NSUTF8StringEncoding error:nil];
    NSLog(@文件讀取成功：%@,content);
    //文件的屬性
    path = NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory, NSUserDomainMask, YES);
    documentsDirectory = [path objectAtIndex:0];
    documentsDirectory = [documentsDirectory stringByAppendingPathComponent:@text];
    documentsDirectory = [documentsDirectory stringByAppendingPathComponent:@123.txt];
    fm = [NSFileManager defaultManager];
    NSDictionary *fileAttributes = [fm attributesOfItemAtPath:documentsDirectory error:nil];
    NSArray *keys;
    id key,value;
    keys = [fileAttributes allKeys];
    int count = [keys count];
    for (int i= 0; i