Netty——网络编程（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: 阻塞模式服务端代码示例（使用nio实现）
 * @author: xz
 * @create: 2022-08-15 21:21
 */
@Slf4j
public class TestServer {
    public static void main(String[] args) throws IOException {
        nioBlockServer();
    }

    /**
     * 使用nio来理解阻塞模式(单线程服务端)
     * */
    private static void nioBlockServer() throws IOException {
        //1、创建ByteBuffer，容量16
        ByteBuffer byteBuffer = ByteBuffer.allocate(16);
        //2、创建服务器
        ServerSocketChannel ssc = ServerSocketChannel.open();
        //3、绑定监听端口
        ssc.bind(new InetSocketAddress(8080));
        //4、连接集合
        ArrayList channels = new ArrayList();
        while(true){
            log.info("connecting...");
            //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，阻塞方法，线程停止运行
            log.info("create connected SocketChannel... {}", sc);
            //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){
                log.info("before read channel ... {}", channel);
                // 8、 接收客户端发送的数据，从channel中读取数据写入到byteBuffer中
                channel.read(byteBuffer);// 启动客户端，阻塞方法，线程停止运行
                //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: 2022-08-15 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...");

    }
}

   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