Verificar Conexão com Internet com Java

Index.jsp

html>

head>

meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">

title>Verificar Conexão com Internet - > UMC-ASTEC

/head>

body>

form method="get" action="TestarConx">

h5>Caso o parâmetro "url" a ser testada não for definida,

será usado o endereço: "http://www.google.com.br/" como alvo.

input type="text" name="url">

input type="submit" name="name" value="Go!">

/form>

/body>

/html>

Servlet

import java.io.IOException;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

/**

* Servlet implementation class TestarConx

*/

public class TestarConx extends HttpServlet {

private static final long serialVersionUID = 1L;

/**

* @see HttpServlet#HttpServlet()

*/

public TestarConx() {

super();

// TODO Auto-generated constructor stub

}

/**

* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)

*/

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

// TODO Auto-generated method stub

String urlName = request.getParameter("url");

//Caso o parâmetro "url" a ser testada não for definida,

//será usado o endereço: "http://www.google.com.br/" como alvo.

if (urlName.equals("")) {

urlName = "http://www.google.com/";

}

java.net.HttpURLConnection urlConnection = null;

try {

java.net.URL url = new java.net.URL(urlName.toString());

urlConnection = (java.net.HttpURLConnection) url.openConnection();

if (urlConnection.getResponseCode() == java.net.HttpURLConnection.HTTP_OK) {

System.out.println("Sim");

} else {

System.out.println("Não");

}

} catch (Exception e) {

System.out.println("Erro");

} finally {

if (urlConnection != null) {

urlConnection.disconnect();

}

}

}

/**

* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)

*/

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

// TODO Auto-generated method stub

}

}

Obs: no código index.jsp foi retirado o símbolo "<" que inicia as tags do html