参考：http://blog.csdn.net/xyz_lmn/article/details/8968213 感谢这些先行者

文件操作常用操作记录一下：

 //获取沙盒的根路径
    NSString *dirHome = NSHomeDirectory();
    NSLog(@"%@",dirHome);
    //获取Documents目录路径
    NSArray *path = NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory,NSUserDomainMask, YES);
    NSString *documentsDirectory = [path objectAtIndex:0];
    NSLog(@"%@",documentsDirectory);
    //获取Library 目录路径
    path = NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES);
    NSString *libraryDirectory  = [path objectAtIndex:0];
    NSLog(@"%@",libraryDirectory);
    //获取caches目录路径
    path = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
    NSString *caches = [path objectAtIndex:0];
    NSLog(@"%@",caches);
    //获取Tmp 目录路径
    NSString *tmpDirectory = NSTemporaryDirectory();
    NSLog(@"%@",tmpDirectory);
    //创建文件夹
    //1 获得文件路径
    //2 创建文件管理器
    //3 用文件管理器在目录上创建文件
    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(@"文件夹创建成功");
    }
    else
    {
        NSLog(@"文件夹创建失败");
    }
    //创建文件（与文件夹的创建相同）
    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(@"文件夹创建成功");
    }
    else
    {
        NSLog(@"文件夹创建失败");
    }
    //写数据到文件
    path = NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory, NSUserDomainMask, YES);
    documentsDirectory = [path objectAtIndex:0];
    documentsDirectory = [documentsDirectory stringByAppendingPathComponent:@"text"];
    documentsDirectory = [documentsDirectory stringByAppendingPathComponent:@"123.txt"];
    NSString *content = @"文件写入的内容";
    res = [content writeToFile:documentsDirectory atomically:YES encoding:NSUTF8StringEncoding error:nil];
    if(res)
    {
        NSLog(@"文件夹创建成功");
    }
    else
    {
        NSLog(@"文件夹创建失败");
    }
    //读文件数据
    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(@"文件读取成功：%@",content);
    //文件的属性
    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<count; i++)
    {
        key = [keys objectAtIndex:i];
        value = http://www.mamicode.com/[fileAttributes objectForKey:key];>