查看端口是否被关闭

netstat -an | findstr :端口号

netstat -an | findstr :80

TCP    0.0.0.0:80           0.0.0.0:0              LISTENING

netstat -tuln | grep :端口号

netstat -tuln | grep :80

ss -tuln | grep :端口号

ss -tuln | grep :80

import socket

def check_port(ip, port):
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    result = sock.connect_ex((ip, port))
    sock.close()
    return result == 0

ip = '127.0.0.1'
port = 80
if check_port(ip, port):
    print(f"Port {port} is open")
else:
    print(f"Port {port} is closed")

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

public class PortChecker {
    public static boolean isPortOpen(String ip, int port) {
        try (Socket socket = new Socket(ip, port)) {
            return true;
        } catch (IOException e) {
            return false;
        }
    }

    public static void main(String[] args) {
        String ip = "127.0.0.1";
        int port = 80;
        if (isPortOpen(ip, port)) {
            System.out.println("Port " + port + " is open");
        } else {
            System.out.println("Port " + port + " is closed");
        }
    }
}

nmap -p 端口号 ip地址

nmap -p 80 192.168.1.1

TCP    0.0.0.0:80           0.0.0.0:0              LISTENING