Netty——网络编程（非阻塞理解及代码示例）

服务端代码

package com.example.nettytest.nio.day3;

import lombok.extern.slf4j.Slf4j;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.*;
import java.util.ArrayList;
import java.util.Iterator;

import static com.example.nettytest.nio.day1.ByteBufferUtil.debugRead;
/**
 * @description: 非阻塞模式服务端代码示例（使用nio实现）
 * @author: xz
 * @create: 2022-08-16 21:21
 */
@Slf4j
public class TestServer {
    public static void main(String[] args) throws IOException {
        nioNoBlockServer();
    }
    
    /**
     * 使用nio来理解非阻塞模式(单线程服务端)
     * */
    private static void nioNoBlockServer() throws IOException {
        //1、创建ByteBuffer，容量16
        ByteBuffer byteBuffer = ByteBuffer.allocate(16);
        //2、创建服务器
        ServerSocketChannel ssc = ServerSocketChannel.open();
        ssc.configureBlocking(false);//ssc设置为非阻塞模式
        //3、绑定监听端口
        ssc.bind(new InetSocketAddress(8080));
        //4、连接集合
        ArrayList channels = new ArrayList();
        while(true){
            //5、accept() 建立与客户端连接, SocketChannel 用来与客户端之间通信
            SocketChannel sc = ssc.accept();//启动服务端，非阻塞方法，线程会继续运行。如果没有建立连接 sc=null
            if(sc !=null){
                log.info("create connected SocketChannel... {}", sc);
                sc.configureBlocking(false);//sc设置为非阻塞模式
                //6、建立的客户端连接sc 添加到 连接集合channels中
                channels.add(sc);
            }
            //7、遍历连接集合
            for(SocketChannel channel : channels){
                // 8、 接收客户端发送的数据，从channel中读取数据写入到byteBuffer中
                int read = channel.read(byteBuffer);// 启动客户端，非阻塞方法，线程会继续运行，read 返回 0
                if(read>0){
                    //切换读模式
                    byteBuffer.flip();
                    //打印可读取内容（从byteBuffer中读取数据内容）
                    debugRead(byteBuffer);
                    //切换回写模式
                    byteBuffer.clear();
                    log.info("after read channel ... {}", channel);
                }
            }
        }
    }
}

客户端代码

package com.example.nettytest.nio.day3;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.SocketAddress;
import java.nio.channels.SocketChannel;
/**
 * @description:
 * @author: xz
 * @create: 2022-08-16 21:45
 */
public class TestClient {
    public static void main(String[] args) throws IOException {
        SocketChannel sc = SocketChannel.open();
        sc.connect(new InetSocketAddress("localhost", 8080));
        SocketAddress address = sc.getLocalAddress();
        //debug模式后，点击src参数，右键选择 输入表达式sc.write(Charset.defaultCharset().encode("hello"));然后执行
        System.out.println("waiting...");
    }
}

工具类，打印输入、输出数据使用

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