代码1

//客户端
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.Socket;

public class Client {
    public static void main(String[] args) throws IOException {
        //创建客户端socket
        Socket socket=new Socket("localhost",8888);
        //获取输出流对象
        OutputStream os = socket.getOutputStream();
        DataOutputStream dos = new DataOutputStream(os);
        //写出数据
        dos.writeUTF("你好啊，弟弟");
        //关闭客户端socket，关闭流
        dos.close();
        socket.close();
    }
}


//服务端
import java.io.DataInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.ServerSocket;
import java.net.Socket;

public class Server {
    public static void main(String[] args) throws IOException {
        //创建socket服务端对象
        ServerSocket serverSocket=new ServerSocket(8888);
        //获取来连接的客户端socket对象
        Socket socket=serverSocket.accept();
        //获取输入流对象
        InputStream inputStream=socket.getInputStream();
        DataInputStream dis=new DataInputStream(inputStream);
        //取出数据
        String s = dis.readUTF();
        System.out.println("收到消息：\t"+s);
        //关闭资源
        dis.close();
        serverSocket.close();
    }
}

代码2