java 判断远程主机的端口是否开通

java 判断远程主机的端口是否开通

import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.util.Objects;

public class SocketJava {
    
    
    public static void main(String[] args) {
    
    
        if(Objects.isNull(args) || args.length != 2){
    
    
            System.out.println("Usage: IP Port");
            return;
        }
        String ip = args[0];
        int port = Integer.valueOf(args[1]);
        try(Socket socket = new Socket()){
    
    
            socket.connect(new InetSocketAddress(ip,port));
            System.out.println(ip + " " + port + " success");
        }catch (IOException e){
    
    
            System.out.println(e.getMessage());
            System.out.println();
            System.out.println(ip + " " + port + " failed");
        }
    }
}

1. 程序员就不应该用Telnet，使用TCP

root@c8f13428e462:/# javac SocketJava.java
root@c8f13428e462:/# ls
SocketJava.class  SocketJava.java  bin  boot  dev  etc  home  lib  lib64  media  mnt  opt  proc  root  run  sbin  srv  sys  tmp  usr  var
root@c8f13428e462:/# java SocketJava
Usage: IP Port
root@c8f13428e462:/#
root@c8f13428e462:/# java SocketJava 192.168.11.119
Usage: IP Port
root@c8f13428e462:/# java SocketJava 192.168.11.119 8080
Connection refused (Connection refused)

192.168.11.119 8080 failed
root@c8f13428e462:/# java SocketJava 192.168.11.119 13306
192.168.11.119 13306 success
root@c8f13428e462:/#
root@c8f13428e462:/# java SocketJava 192.168.11.119 138083
Exception in thread "main" java.lang.IllegalArgumentException: port out of range:138083
        at java.net.InetSocketAddress.checkPort(InetSocketAddress.java:143)
        at java.net.InetSocketAddress.<init>(InetSocketAddress.java:224)
        at SocketJava.main(SocketJava.java:16)
root@c8f13428e462:/# java SocketJava 192.168.11.119 8083
Connection refused (Connection refused)

192.168.11.119 8083 failed
root@c8f13428e462:/# java SocketJava 192.168.11.119 18083
192.168.11.119 18083 success

2. 清爽啊