Question:
I would like to create a very simple applet that pings anIP address and returns a message stating whether that IP is alive. Icouldn’t find any straightforward answers to my problem in thejava.net
package. How can I create a program with Java that performs this task?
Answer:
I created a little client program that opens a connection to the echoserver (always port 7) of a given host (using the domain name insteadof the IP address, hope that’s okay), sends the string “Hello,” readsthe response, then compares it with the string sent:
import java.io.*;import java.net.*;class Ping { public static void main(String args[]) { try { Socket t = new Socket(args[0], 7); DataInputStream is = new DataInputStream(t.getInputStream()); PrintStream os = new PrintStream(t.getOutputStream()); os.println(“Hello”); String str = is.readLine(); if (str.equals(“Hello”)) System.out.println(“Alive :-)”) ; else System.out.println(“Dead :-(“); t.close(); } catch (IOException e) {System.out.println(“Error: ” + e);} }}