Objective-C: NSFileManager 的使用

- (void)testFileCreate
{
    NSFileManager *fileManager = [NSFileManager defaultManager];
    NSString *filePath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject];
    filePath = [filePath stringByAppendingPathComponent:@"new.txt"];
    NSLog(@"filePath = %@",filePath);
    // 判断文件是否存在
    if (![fileManager fileExistsAtPath:filePath]){
        // 若文件不存在，则新建文件
        [fileManager createFileAtPath:filePath contents:nil attributes:nil];
    }
    // 向文件中写内容，通过文件句柄，NSFileHandle实现
    NSFileHandle *fileHandle = [NSFileHandle fileHandleForWritingAtPath:filePath];
    NSString *content = @"hey,brother.This is a test.";
    NSData *contentData = [content dataUsingEncoding:NSUTF8StringEncoding];
    [fileHandle writeData:contentData];
    // 关闭文件
    [fileHandle closeFile];
    
    // 读取文件中的内容
    fileHandle = [NSFileHandle fileHandleForReadingAtPath:filePath];
    NSData *readData = [fileHandle readDataToEndOfFile];
    // data 转 NSString
    NSString *readStr = [[NSString alloc] initWithData:readData encoding:NSUTF8StringEncoding];
    NSLog(@"readStr = %@",readStr);
    [fileHandle closeFile];
    // 直接以NSString 的方式读取文件
    NSString *contentStr = [NSString stringWithContentsOfFile:filePath encoding:NSUTF8StringEncoding error:nil];
    NSLog(@"contentStr = %@",contentStr);
}

- (void)testFileOperation
{
    // 获得临时目录
    NSString *tempPath = NSTemporaryDirectory();
    NSLog(@"tempPath = %@",tempPath);
    // 最后一级目录
    NSLog(@"last = %@", [tempPath lastPathComponent] );
    // 在最后增加一级目录，原目录不变，返回一个新的目录字符串
    NSLog(@"add last = %@",[tempPath stringByAppendingPathComponent:@"add"]);
    // 删除最后一级目录，原目录不变，返回一个新的目录字符串
    NSLog(@"del last = %@",[tempPath stringByDeletingLastPathComponent]);
    NSString *filePath = [tempPath stringByAppendingPathComponent:@"test.txt"];
    NSLog(@"filePath = %@",filePath);
    // 扩展名，输出为 txt
    NSLog(@"extension = %@",[filePath pathExtension]);
    NSFileManager *manager = [NSFileManager defaultManager];
    if(![manager fileExistsAtPath:filePath]){
        [manager createFileAtPath:filePath contents:nil attributes:nil];
    }
    
    NSString *newPath = [tempPath stringByAppendingPathComponent:@"newtest.txt"];
    // 拷贝文件
    [manager copyItemAtPath:filePath toPath:newPath error:nil];
    if([manager fileExistsAtPath:newPath]){
        NSLog(@"copy success");
    }
    // 删除文件
    [manager removeItemAtPath:newPath error:nil];
    if(![manager fileExistsAtPath:newPath]){
        NSLog(@"remove success");
    }
    
    // 文件是否可读
    if([manager isReadableFileAtPath:filePath]){
        NSLog(@"readable");
    }
    // 文件是否可写
    if([manager isWritableFileAtPath:filePath]){
        NSLog(@"writeable");
    }
}