客户端

import java.io.PrintWriter;
import java.net.Socket;

public class TcpClient {
    public static void main(String[] args) throws Exception {
        String msg = "hello world 你好世界";
        //创建一个Socket,和本机的8888端口进行连接
        Socket socket = new Socket("127.0.0.1", 8888);
        //使用Socket创建一个PrintWriter进行写数据
        PrintWriter printWriter = new PrintWriter(socket.getOutputStream());
        //发送数据
        printWriter.println(msg);
        //刷新一下，使得服务立马可以收到请求信息
        printWriter.flush();
        //关闭资源
        printWriter.close();
        socket.close();
    }
}

服务端

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.ServerSocket;
import java.net.Socket;

public class TcpServer {
    public static void main(String[] args) throws Exception {
        //创建serverSocket监听一个端8888
        ServerSocket serverSocket = new ServerSocket(8888);
        System.out.println("TCP服务器已经启动，端口是8888");
        //无限循环
        while (true) {
            //等待客户端的请求
            Socket socket = serverSocket.accept();
            BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream(),"UTF-8"));
            String buffer = null;
            while ((buffer = reader.readLine()) != null && !buffer.equals("")) {
                System.out.println(buffer);
            }
            //通过Socket对象得到输出流，构造BufferedWrite对象
            BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream(),"UTF-8"));
            //HTTP 请求头信息
            writer.write("HTTP/1.1 200 OK \r\n Content-Type:text/html \r\n  ");
            //写一些html体
            writer.write("<html><head><title>http请求</title></head><body>这是一个HTTP请求</body></html>");
            //刷新输出流，使得数据立马发送
            writer.flush();
            //关闭
            reader.close();
            writer.close();
            socket.close();
        }
    }
}