05-Java NIO 编程 零拷贝 与 AIO

package com.dance.netty.nio.demo.zerocopy;

import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;

public class ZeroCopyServer {

    public static void main(String[] args) throws Exception {

        InetSocketAddress inetSocketAddress = new InetSocketAddress(7001);

        ServerSocketChannel open = ServerSocketChannel.open();

        open.socket().bind(inetSocketAddress);

        for (;;){
            SocketChannel accept = open.accept();
            int countSize = 0;
            ByteBuffer allocate = ByteBuffer.allocate(4096);
            while (-1 != countSize){
                countSize  = accept.read(allocate);
                allocate.rewind(); // 倒置 position=0 Mark 作废
            }
        }

    }

}

package com.dance.netty.nio.demo.zerocopy;

import java.io.File;
import java.io.FileInputStream;
import java.net.InetSocketAddress;
import java.nio.channels.FileChannel;
import java.nio.channels.SocketChannel;
import java.time.Duration;
import java.time.Instant;

public class ZeroCopyClient {

    public static void main(String[] args) throws Exception {

        SocketChannel open = SocketChannel.open();
        boolean connect = open.connect(new InetSocketAddress(7001));

        // 获取文件Channel
        File file = new File("src/main/resources/01.jpeg");
        FileChannel channel = new FileInputStream(file).getChannel();

        Instant startTime = Instant.now();

        /*
         * 在Linux下,一个transferTo方法就可以传输完成
         * 在Windows下,调用一次transferTo 只能传输8M,就需要分段传输文件,而且要记录传输时的位置
         * transferTo 底层使用零拷贝
         */
        long l = channel.transferTo(0, channel.size(), open);
        System.out.println(l);

        Instant endTime = Instant.now();
        System.out.println("用时:" + Duration.between(startTime,endTime).toMillis() + "ms");
        channel.close();
    }

}

6806
用时:3ms