Get users IP

This code example shows how to obtain the IP address of the user that calls the server.
The Request object has a few neat methods to get information about the call and about the caller, and one of them is named getRemoteAddr() which returns the IP address of the calling computer.
In the example below we print out the IP address on a blank html-page.


import java.io.*;
import java.util.Enumeration;

import javax.servlet.*;
import javax.servlet.http.*;

/**
* Example Servlet
* @author http://www.javadb.com
*/
public class ExampleServlet extends HttpServlet {

/** Processes requests for both HTTP GET and POST methods.
* @param request servlet request
* @param response servlet response
*/
protected void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {

response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();

printPageStart(out);

//Print out the IP address of the caller
out.println(request.getRemoteAddr());

printPageEnd(out);
}

/** Prints out the start of the html page
* @param out the PrintWriter object
*/
private void printPageStart(PrintWriter out) {

out.println("");
out.println("");
out.println("Example Servlet of how to display users IP-address");
out.println("");
out.println("");

}

/** Prints out the end of the html page
* @param out the PrintWriter object
*/
private void printPageEnd(PrintWriter out) {

out.println("");
out.println("");
out.close();
}
}

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