NSFileManager是个单例类，也是一个文件管理器。可以通过NSFileManager创建文件夹、创建文件、写文件、读文件内容等等基本功能。

我们在Documents里面进行举例，首先是获取Documents的路径。

 //获取Documents路径
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *path = [paths objectAtIndex:0];
    NSLog(@"path:%@", path);

创建文件夹

    NSArray *documentArray = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentPath = [documentArray firstObject];
    NSLog(@"documentPath = %@",documentPath);
    
    NSString *filePath = [documentPath stringByAppendingPathComponent:@"ios"];
    
   BOOL isSuccess =  [[NSFileManager defaultManager] createDirectoryAtPath:filePath withIntermediateDirectories:YES attributes:nil error:nil];
    NSLog(@"%d",isSuccess);

创建文件

    NSArray *documentArray = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentPath = [documentArray firstObject];
    NSLog(@"documentPath = %@",documentPath);
    
    NSString *filePath = [documentPath stringByAppendingPathComponent:@"ios.txt"];
    
    [[NSFileManager defaultManager] createFileAtPath:filePath contents:nil attributes:nil];

写文件

    NSString *documentsPath =[self getDocumentsPath];
    NSString *iOSPath = [documentsPath stringByAppendingPathComponent:@"iOS.txt"];
    NSString *content = @"我要写数据啦";
    BOOL isSuccess = [content writeToFile:iOSPath atomically:YES encoding:NSUTF8StringEncoding error:nil];

读取文件内容

    NSString *documentsPath =[self getDocumentsPath];
    NSString *iOSPath = [documentsPath stringByAppendingPathComponent:@"iOS.txt"];
    NSString *content = [NSString stringWithContentsOfFile:iOSPath encoding:NSUTF8StringEncoding error:nil];
    NSLog(@"read success: %@",content);

判断文件是否存在

NSString *filePath = [documentPath stringByAppendingPathComponent:@"ios.txt"];
    
   BOOL isExist = [[NSFileManager defaultManager] fileExistsAtPath:filePath];

计算文件大小

- (unsigned long long)fileSizeAtPath:(NSString *)filePath{
    NSFileManager *fileManager = [NSFileManager defaultManager];
    BOOL isExist = [fileManager fileExistsAtPath:filePath];
    if (isExist){
        unsigned long long fileSize = [[fileManager attributesOfItemAtPath:filePath error:nil] fileSize];
        return fileSize;
    } else {
        NSLog(@"file is not exist");
        return 0;
    }
}

计算整个文件夹中所有文件大小

- (unsigned long long)folderSizeAtPath:(NSString*)folderPath{
    NSFileManager *fileManager = [NSFileManager defaultManager];
    BOOL isExist = [fileManager fileExistsAtPath:folderPath];
    if (isExist){
        NSEnumerator *childFileEnumerator = [[fileManager subpathsAtPath:folderPath] objectEnumerator];
        unsigned long long folderSize = 0;
        NSString *fileName = @"";
        while ((fileName = [childFileEnumerator nextObject]) != nil){
            NSString* fileAbsolutePath = [folderPath stringByAppendingPathComponent:fileName];
            folderSize += [self fileSizeAtPath:fileAbsolutePath];
        }
        return folderSize / (1024.0 * 1024.0);
    } else {
        NSLog(@"file is not exist");
        return 0;
    }
}

删除文件

-(void)deleteFile{
    NSString *documentsPath =[self getDocumentsPath];
    NSFileManager *fileManager = [NSFileManager defaultManager];
    NSString *iOSPath = [documentsPath stringByAppendingPathComponent:@"iOS.txt"];
    BOOL isSuccess = [fileManager removeItemAtPath:iOSPath error:nil];
    if (isSuccess) {
        NSLog(@"delete success");
    }else{
        NSLog(@"delete fail");
    }
}

移动文件

- (void)moveFileName
{
    NSString *documentsPath =[self getDocumentsPath];
    NSFileManager *fileManager = [NSFileManager defaultManager];
    NSString *filePath = [documentsPath stringByAppendingPathComponent:@"iOS.txt"];
    NSString *moveToPath = [documentsPath stringByAppendingPathComponent:@"ios/qq"];
    BOOL isSuccess = [fileManager moveItemAtPath:filePath toPath:moveToPath error:nil];
    if (isSuccess) {
        NSLog(@"rename success");
    }else{
        NSLog(@"rename fail");
    }
}

重命名

- (void)renameFileName
{
    //通过移动该文件对文件重命名
    NSString *documentsPath =[self getDocumentsPath];
    NSFileManager *fileManager = [NSFileManager defaultManager];
    NSString *filePath = [documentsPath stringByAppendingPathComponent:@"iOS.txt"];
    NSString *moveToPath = [documentsPath stringByAppendingPathComponent:@"rename.txt"];
    BOOL isSuccess = [fileManager moveItemAtPath:filePath toPath:moveToPath error:nil];
    if (isSuccess) {
        NSLog(@"rename success");
    }else{
        NSLog(@"rename fail");
    }
}