编写程序,完成如下功能:有1台服务器端和10台客户端,服务服务器端向10个客户端发送消息"连接上服务器......",客户端收到消息后在控制台打印出消息,用Java语言实现

以下是一个简单的实现，使用了Java中的Socket和ServerSocket类实现TCP连接：

服务器端代码：

import java.io.IOException;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;

public class Server {

    public static void main(String[] args) throws IOException {
        ServerSocket serverSocket = new ServerSocket(8080);
        System.out.println("Server started.");

        for (int i = 1; i <= 10; i++) {
            Socket client = serverSocket.accept();
            System.out.println("Client " + i + " connected.");
            OutputStream out = client.getOutputStream();
            out.write("Connected to server...".getBytes());
            out.flush();
            out.close();
        }

        serverSocket.close();
        System.out.println("Server closed.");
    }
}

客户端代码：

import java.io.IOException;
import java.io.InputStream;
import java.net.Socket;

public class Client {

    public static void main(String[] args) throws IOException {
        Socket socket = new Socket("localhost", 8080);
        InputStream in = socket.getInputStream();
        byte[] buffer = new byte[1024];
        int len = in.read(buffer);
        System.out.println(new String(buffer, 0, len));
        in.close();
        socket.close();
    }
}

在运行程序之前，需要先启动服务器端，然后再启动10个客户端。在客户端控制台上将会输出"Connected to server..."消息。