0、判断一个文件是否存在,传入全路径(fileExistsAtPath)

// 创建文件管理器
NSFileManager * fileManager = [NSFileManager defaultManager];

NSString * documents = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)lastObject];
NSString * filePath = [documents stringByAppendingPathComponent:@"test"];

    // 判断一个文件是否存在,传入全路径
    if ([fileManager fileExistsAtPath:filePath]) {
        NSLog(@"it is exit");
    }

1、在Documents里创建目录

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);    
   NSString *documentsDirectory = [paths objectAtIndex:0];    
   NSLog(@"documentsDirectory%@",documentsDirectory);    
   NSFileManager *fileManager = [NSFileManager defaultManager];    
   NSString *testDirectory = [documentsDirectory stringByAppendingPathComponent:@"test"];    
   // 创建目录  
   [fileManager createDirectoryAtPath:testDirectory withIntermediateDirectories:YES attributes:nil error:nil];  

2、在目录下创建文件

NSString *testPath = [testDirectory stringByAppendingPathComponent:@"test00.txt"];    
NSString *testPath2 = [testDirectory stringByAppendingPathComponent:@"test22.txt"];    
NSString *testPath3 = [testDirectory stringByAppendingPathComponent:@"test33.txt"];    
  
  
NSString *string = @"写入内容，write String";  
[fileManager createFileAtPath:testPath contents:[string  dataUsingEncoding:NSUTF8StringEncoding] attributes:nil];  
[fileManager createFileAtPath:testPath2 contents:[string  dataUsingEncoding:NSUTF8StringEncoding] attributes:nil];  
[fileManager createFileAtPath:testPath3 contents:[string  dataUsingEncoding:NSUTF8StringEncoding] attributes:nil];  

3、获取目录列里所有文件名

两种方法获取：subpathsOfDirectoryAtPath 和subpathsAtPath

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);    
NSString *documentsDirectory = [paths objectAtIndex:0];    
NSLog(@"documentsDirectory%@",documentsDirectory);    
NSFileManager *fileManage = [NSFileManager defaultManager];    
NSString *myDirectory = [documentsDirectory stringByAppendingPathComponent:@"test"];    
NSArray *file = [fileManage subpathsOfDirectoryAtPath: myDirectory error:nil];   
NSLog(@"%@",file);    
NSArray *files = [fileManage subpathsAtPath: myDirectory ];   
NSLog(@"%@",files);  

4、fileManager使用操作当前目录

//创建文件管理器  
    NSFileManager *fileManager = [NSFileManager defaultManager];  
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);  
    NSString *documentsDirectory = [paths objectAtIndex:0];  
    //更改到待操作的目录下  
    [fileManager changeCurrentDirectoryPath:[documentsDirectory stringByExpandingTildeInPath]];  
    //创建文件fileName文件名称，contents文件的内容，如果开始没有内容可以设置为nil，attributes文件的属性，初始为nil  
    NSString * fileName = @"testFileNSFileManager.txt";  
    NSArray *array = [[NSArray alloc] initWithObjects:@"hello world",@"hello world1", @"hello world2",nil];  
    [fileManager createFileAtPath:fileName contents:array attributes:nil]; 

5、删除文件

[fileManager removeItemAtPath:fileName error:nil];