IP | Kode Java - Learn Java by Examples

This example show you how to convert a raw IP address, an array of byte, returned by InetAddress.getAddress() method call to its string representation.

package org.kodejava.net;

import java.net.InetAddress;
import java.net.UnknownHostException;

public class RawIPToString {
    public static void main(String[] args) {
        byte[] ip = new byte[0];
        try {
            InetAddress address = InetAddress.getLocalHost();
            ip = address.getAddress();
        } catch (UnknownHostException e) {
            e.printStackTrace();
        }
        String ipAddress = RawIPToString.getIpAddress(ip);
        System.out.println("IP Address = " + ipAddress);

        try {
            InetAddress address = InetAddress.getByName("google.com");
            ip = address.getAddress();
        } catch (UnknownHostException e) {
            e.printStackTrace();
        }
        ipAddress = RawIPToString.getIpAddress(ip);
        System.out.println("IP Address = " + ipAddress);
    }

    /**
     * Convert raw IP address to string.
     *
     * @param rawBytes raw IP address.
     * @return a string representation of the raw ip address.
     */
    private static String getIpAddress(byte[] rawBytes) {
        int i = 4;
        StringBuilder ipAddress = new StringBuilder();
        for (byte raw : rawBytes) {
            ipAddress.append(raw & 0xFF);
            if (--i > 0) {
                ipAddress.append(".");
            }
        }
        return ipAddress.toString();
    }
}

This example will print something like:

IP Address = 30.30.30.60
IP Address = 142.251.10.113

package org.kodejava.servlet; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.IOException; import java.io.PrintWriter; @WebServlet(name = "ClientAddressServlet", urlPatterns = "/client-ip") public class ClientAddressServlet extends HttpServlet { @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // Get client's IP address String clientIP = request.getRemoteAddr(); // Get client's host name String clintHost = request.getRemoteHost(); response.setContentType("text/plain"); PrintWriter out = response.getWriter(); out.println("IP : " + clientIP); out.println("Host: " + clintHost); } @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doPost(request, response); } }

Tag Archives: IP

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