使用文件指针操作文件

- (IBAction)useFileHandler

{

    NSString *documentsPath = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents"];

    NSString *filePath = [documentsPath stringByAppendingPathComponent:@"filea.txt"];

    NSLog(@"%@", filePath);

    

    NSString *content = @"您好";

    

    //1. 创建文件

    [[NSFileManager defaultManager]createFileAtPath:filePath contents:nil attributes:nil];

    //2. 创建FileHandle

    NSFileHandle *writingHandle = [NSFileHandle fileHandleForWritingAtPath:filePath];

    //NSString ==> NSData

    //3. 准备数据

    NSData *data = [content dataUsingEncoding:NSUTF8StringEncoding];

    //4. 写入数据

    [writingHandle writeData:data];

    //5. 关闭fileHandle

    [writingHandle closeFile];

    

    //练习：从刚才的文件中使用fileHandle读取数据

    NSFileHandle *readHandle = [NSFileHandle fileHandleForReadingAtPath:filePath];

    data = [readHandle readDataToEndOfFile];

    NSString *readString = [[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];

    NSLog(@"read:%@", readString);

    

    

}