Netty—— AIO示例代码

示例代码

package com.example.nettytest.nio.day3;

import lombok.extern.slf4j.Slf4j;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.AsynchronousFileChannel;
import java.nio.channels.CompletionHandler;
import java.nio.file.Paths;
import java.nio.file.StandardOpenOption;
import static com.example.nettytest.nio.day1.ByteBufferUtil.debugAll;

@Slf4j
public class AioFileChannel {
    public static void main(String[] args) throws IOException {
        try (AsynchronousFileChannel channel = AsynchronousFileChannel.open(Paths.get("data.txt"), StandardOpenOption.READ)) {
            ByteBuffer buffer = ByteBuffer.allocate(16);
            log.debug("线程"+Thread.currentThread().getName()+":"+"read begin...");
            /**
             *  channel.read 异步操作
             *参数1 ByteBuffer
             *参数2 读取的起始位置
             *参数3 附件
             *参数4 回调对象 CompletionHandler
             * */
            channel.read(buffer, 0, buffer, new CompletionHandler() {
                @Override //文件读取成功
                public void completed(Integer result, ByteBuffer attachment) {
                    log.debug("线程"+Thread.currentThread().getName()+"：read completed...{}", result);
                    attachment.flip();
                    debugAll(attachment);
                }
                @Override //文件读取失败
                public void failed(Throwable exc, ByteBuffer attachment) {
                    exc.printStackTrace();
                }
            });
            log.debug("线程"+Thread.currentThread().getName()+"：read end...");
        } catch (IOException e) {
            e.printStackTrace();
        }
        //主线程先接收控制台输出，如果没有输出即停止在此处
        System.in.read();
    }
}

输出结果工具类

package com.example.nettytest.nio.day1;

import io.netty.util.internal.StringUtil;

import java.nio.ByteBuffer;

import static io.netty.util.internal.MathUtil.isOutOfBounds;
import static io.netty.util.internal.StringUtil.NEWLINE;

public class ByteBufferUtil {
    private static final char[] BYTE2CHAR = new char[256];
    private static final char[] HEXDUMP_TABLE = new char[256 * 4];
    private static final String[] HEXPADDING = new String[16];
    private static final String[] HEXDUMP_ROWPREFIXES = new String[65536 >>> 4];
    private static final String[] BYTE2HEX = new String[256];
    private static final String[] BYTEPADDING = new String[16];

    static {
        final char[] DIGITS = "0123456789abcdef".toCharArray();
        for (int i = 0; i  4 & 0x0F];
            HEXDUMP_TABLE[(i