服务端开启一个端口，收到请求后立即初始化一个线程进行处理！
线程为一个内部类，不断从管道中读取字节流然后打印，并且将字节流内容加倍后返回！
客户端循环不断向服务端发送数据并接收返回数据进行打印！
至今运行看效果！
此示例为最简单的示例程序，不完善地方多指教！

服务端：

package com.socket;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.InetSocketAddress;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketAddress;
import java.util.Arrays;
/**
 * @说明 监听端口服务
 * @author cuisuqiang
 * @version 1.0
 * @since
 */
public class SocketService {
	public static void main(String[] args) {
		try {
			// 创建非邦定式连接对象
			ServerSocket ss = new ServerSocket();
			// 连接地址对象
			SocketAddress address = new InetSocketAddress("192.168.9.69", 8001);
			// 将连接对象邦定到地址
			ss.bind(address);
			System.out.println("邦定端口成功：" + address.toString());
			boolean bRunning = true;
			while (bRunning) {
				// 接收请求
				Socket s = ss.accept();
				// 将请求指定一个线程去执行
				new Thread(new SocketListener(s)).start();
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
}
/**
 * @说明 监听端口数据并打印
 * @author cuisuqiang
 * @version 1.0
 * @since
 */
class SocketListener implements Runnable {
	Socket socket = null;
	public SocketListener(Socket socket) {
		this.socket = socket;
	}
	@Override
	public void run() {
		System.err.println("开始处理：" + socket.toString());
		try {
			InputStream ips = socket.getInputStream();
			OutputStream ops = socket.getOutputStream();
			while (true) {
				byte[] bts = readStream(ips);
				if (null != bts) {
					System.err.println("接收：" + Arrays.toString(bts));
					byte[] btreturn = new byte[bts.length * 2];
					System.arraycopy(bts, 0, btreturn, 0, bts.length);
					System.arraycopy(bts, 0, btreturn, bts.length - 1, bts.length);
					ops.write(btreturn);
					ops.flush();
				}
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
		System.err.println("执行结束：" + socket.toString());
	}
	/**
	 * 读取流 5 秒超时 1 秒一次
	 */
	public byte[] readStream(InputStream inStream) throws Exception {
		int count = 0;
		int index = 1;
		while (count == 0) {
			count = inStream.available();
			index++;
			Thread.sleep(1 * 1000);
			if (index > 5 || count > 0) {
				break;
			}
		}
		if (count > 0) {
			byte[] b = new byte[count];
			inStream.read(b);
			return b;
		}
		return null;
	}
}

客户端：

package com.socket;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;
import java.util.Arrays;
/**
 * @说明 Socket客户端，连接成功后发送一组数据然后关闭连接
 * @author cuisuqiang
 * @version 1.0
 * @since
 */
public class SocketClient {
	public static void main(String[] args) {
		try {
			Socket socket = new Socket("192.168.9.69", 8001);
			socket.setKeepAlive(true);
			InputStream ips = socket.getInputStream();
			OutputStream ops = socket.getOutputStream();
			while(true){
				byte[] remess = new byte[20];
				for (int i = 0; i < 20; i++) {
					remess[i] = (byte) i;
				}
				ops.write(remess);
				byte[] bts = readStream(ips);
				if (null != bts) {
					System.err.println("返回：" + Arrays.toString(bts));
				}
				Thread.sleep(2 * 1000);
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
	/**
	 * 读取流 5 秒超时 1 秒一次
	 */
	public static byte[] readStream(InputStream inStream) throws Exception {
		int count = 0;
		int index = 1;
		while (count == 0) {
			count = inStream.available();
			index++;
			Thread.sleep(1 * 1000);
			if (index > 5 || count > 0) {
				break;
			}
		}
		if (count > 0) {
			byte[] b = new byte[count];
			inStream.read(b);
			return b;
		}
		return null;
	}
}

服务端打印：

邦定端口成功：/192.168.9.69:8001
开始处理：Socket[addr=/192.168.9.69,port=5865,localport=8001]
接收：[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19]
接收：[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19]
接收：[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19]

客户端打印：

返回：[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 0]
返回：[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 0]
返回：[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 0]

// 创建非邦定式连接对象
ServerSocket ss = new ServerSocket();
// 连接地址对象
SocketAddress address = new InetSocketAddress("192.168.9.69", 8001);
// 将连接对象邦定到地址
ss.bind(address);
System.out.println("邦定端口成功：" + address.toString());

也许大家看到的网上示例不是这么写的，而是直接邦定一个端口！
可是一台机器不可能只有一个网卡的，有的还可能设置了兼容IP！
为了不歧义，这里直接邦定某IP的某端口，当然这个IP运行环境的IP地址！