In this example we are going to see how to get client’s address and hostname in a Servlet. Java offers a very convenient way to handle client and server information such as hostname ip address etc.
Getting a client’s address and hostname requires that you:
- Get clients ip adfress using
HttpServletRequest.getRemoteAddr(). - Get clients hostname using
HttpServletRequest.getRemoteHost().
Take a look at the code snippets that follow:
package com.javacodegeeks.snippets.enterprise;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class GetClientAddressAndHostnameInServlet extends HttpServlet {
private static final long serialVersionUID = -2128122335811219481L;
public void doGet(HttpServletRequest req, HttpServletResponse res) throws IOException {
PrintWriter out = res.getWriter();
res.setContentType("text/plain");
// client's IP address
String remoteAddr = req.getRemoteAddr();
// client's hostname
String remoteHost = req.getRemoteHost();
out.write("remoteAddr = ");
out.write(remoteAddr);
out.write("n");
out.write("remoteHost = ");
out.write(remoteHost);
out.close();
}
}web.xml
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" version="2.5"> <display-name>JCG Snippets Web Project</display-name> <servlet> <servlet-name>JCG Snippets Application</servlet-name> <servlet-class>com.javacodegeeks.snippets.enterprise.GetClientAddressAndHostnameInServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>JCG Snippets Application</servlet-name> <url-pattern>/jcgservlet</url-pattern> </servlet-mapping> </web-app>
URL:
http://myhost:8080/jcgsnippets/jcgservletOutput:
remoteAddr = 127.0.0.1 remoteHost = mypc
This is an example on how to get client’s address and hostname in a Servlet.
