socket连接阿里云服务器失败解决

简单的socket，连接不到阿里云的服务器。

package socket_guest;

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

public class socket
{
	public static void main(String[] args) throws Exception
	{
		String host="/**/";
		int port=2000;
		Socket socket=new Socket(host,port);
		OutputStream outputStream=socket.getOutputStream();
		String message="amessage";
		socket.getOutputStream().write(message.getBytes("UTF-8"));
		outputStream.close();
		socket.close();
	}
}

package socket;

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

public class receive 
{
	public static void main(String[] args) throws Exception
	{
		int port=2000;
		ServerSocket server=new ServerSocket(port);
		
		Socket socket=server.accept();
		InputStream inputStream =socket.getInputStream();
		byte[] bytes=new byte[1024];
		int len;
		StringBuilder sb=new StringBuilder();
		while((len=inputStream.read(bytes))!=-1)
		{
			sb.append(new String(bytes,0,len,"UTF-8"));
		}
	    System.out.println("get message from client: " + sb);
		inputStream.close();
		socket.close();
		server.close();
	}
}

代码本身是没有问题的，连接不上阿里云。
查明原因：阿里云默认关闭端口
需要在安全设置添加。
选择自定义并设置打开的端口范围即可。