java异步读取文件2种实现

`import com.sun.tools.jconsole.JConsoleContext;

import java.io.;
import java.lang.reflect.Array;
import java.math.BigDecimal;
import java.nio.ByteBuffer;
import java.nio.channels.AsynchronousFileChannel;
import java.nio.channels.CompletionHandler;
import java.nio.channels.FileChannel;
import java.nio.channels.FileLock;
import java.nio.file.OpenOption;
import java.nio.file.Paths;
import java.nio.file.StandardOpenOption;
import java.time.LocalDate;
import java.util.;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.stream.Collectors;
import java.util.stream.Stream;

public class Main {
public static void main(String[] args) throws IOException, ExecutionException, InterruptedException {
/基于Future接口的异步读取文件/
// AsynchronousFileChannel channel = AsynchronousFileChannel.open(Paths.get("G:\C#图解教程（第四版高清）.pdf"), StandardOpenOption.READ);
// ByteBuffer buffer = ByteBuffer.allocateDirect(13010241024);
// var result = channel.read(buffer,0);
// while(!result.isDone())
// {
// System.out.printf("我还没完成呢，宝贝！");
// }
// buffer.flip();//将缓存字节数组的指针设置为数组的开始下标0，否则读的就是最后一个位置byte = 0
// byte[] data = new byte[buffer.limit()];
// buffer.get(data);
// //System.out.println(data.toString());
// buffer.clear();

    /*基于回调的读取文件*/
    var fc = new CompletionHandler<Integer,Object>(){
        @Override
        public void completed(Integer result, Object attachment) {
            System.out.println("我完成了"+result);
        }
        @Override
        public void failed(Throwable exc, Object attachment) {
            System.out.println("我出了点问题！" +exc.getMessage());
        }
    };
    ByteBuffer buffer = ByteBuffer.allocateDirect(130*1024*1024);
    try (AsynchronousFileChannel channel = AsynchronousFileChannel.open(Paths.get("G:\\C#图解教程（第四版高清）.pdf"),StandardOpenOption.READ,StandardOpenOption.WRITE)){
        channel.write(buffer,0,null ,fc);
        Thread.sleep(1000);
    }

}

}

`