How to fix "Problem accessing the absolute URL" exception?

[chaitanya karthikk]

Hi all, I am trying to run the sample code

<%@page language="java" pageEncoding="utf-8" contentType="text/html;charset=utf-8"%>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<c:import var="page" url="http://www.tutorialspoint.com/jsp/jstl_core_import_tag.htm"></c:import>
<c:out value="${page }"></c:out>

I am getting

org.apache.jasper.JasperException: javax.servlet.ServletException: javax.servlet.jsp.JspException: Problem accessing
the absolute URL "http://www.tutorialspoint.com/jsp/jstl_core_import_tag.htm". java.net.ConnectException: Connection refused: connect

There is a OpenDNS like kind of software installed on our network and we are using a proxy server to connect to the internet where all our traffic is screened. The following code is not working.

I referred this link. The author said that the problem was with his DNS settings. However I cant change my DNS settings? What can I do to resolve this issue?

Can anyone please tell me? Thank you all in advance.

[Palak Mathur]

Why do you want to import that page? There is no other way to access that page if you cannot change your DNS settings. Otherwise you may have to make that page available locally.

[chaitanya karthikk]

@Mathur: I am currently working on a project where few pages will be loaded from already existing applications.

I think I got the solution, hope this should work. It is to remove the url to be screened from my proxy server. Wrote a mail to our admin. Request still in process. Don't know whether this fix will work or not.

What do you guys say? any ideas?

[Palak Mathur]

chaitanya karthikk wrote:@Mathur: I am currently working on a project where few pages will be loaded from already existing applications.

I think I got the solution, hope this should work. It is to remove the url to be screened from my proxy server. Wrote a mail to our admin. Request still in process. Don't know whether this fix will work or not.

What do you guys say? any ideas?

Yes, if the admin could provide access to the url, then it will work.

[chaitanya karthikk]

I would also like to know whether this problem has something to do with the VM parameters. Can I place my proxy id and password in the VM parameters list and try streaming the page? I read about the same kind of problem in a post here

http://support.sas.com/kb/16/958.html

However I could not understand few things in it because I have zero knowledge about VM parameters. Never heard about them and read about them.

[Palak Mathur]

chaitanya karthikk wrote:I would also like to know whether this problem has something to do with the VM parameters. Can I place my proxy id and password in the VM parameters list and try streaming the page? I read about the same kind of problem in a post here

http://support.sas.com/kb/16/958.html

However I could not understand few things in it because I have zero knowledge about VM parameters. Never heard about them and read about them.

You can try putting these parameters in the file you use to start your servlet container (server start file). And check if it works.

[chaitanya karthikk]

@Mathur: I tried my my attempt has failed. I gave my proxy details and proxy port. But I cant find an option to get the proxy password.

Can you please suggest me? Thank you in advance.

[Palak Mathur]

chaitanya karthikk wrote:@Mathur: I tried my my attempt has failed. I gave my proxy details and proxy port. But I cant find an option to get the proxy password.

Can you please suggest me? Thank you in advance.

Add following:-

-Dhttp.proxyUser=${userName}
-Dhttp.proxyPassword=${password}

[chaitanya karthikk]

@Mathur: I tried with these settings

-Dhttp.proxyUser=akash.malwa.proxy
-Dhttp.proxyPassword=logmein667#
-Dhttp.proxyHost=192.168.6.241
-Dhttp.proxyPost=8080

Previously I got Connection refused: connect, exception. Now I am getting a FileNotFoundException. The full stack trace is

javax.servlet.jsp.JspException: Problem accessing the absolute URL "http://www.dodge.com/en/includes/vendor_footer.html".
 java.io.FileNotFoundException: http://www.dodge.com/en/includes/vendor_footer.html
	at org.apache.taglibs.standard.tag.common.core.ImportSupport.acquireReader(ImportSupport.java:381)
	at org.apache.taglibs.standard.tag.common.core.ImportSupport.acquireString(ImportSupport.java:251)
	at org.apache.taglibs.standard.tag.common.core.ImportSupport.doEndTag(ImportSupport.java:168)
	at net.autodata.framework.web.servlet.tags.CachedImportTag.doEndTag(CachedImportTag.java:47)
	at org.apache.jsp.tag.meta.http_003a.autodata_net.chrysler.us.brands.tags.layout.layout.master_tag._jspx_meth_asc_005fcachedImport_005f3(master_tag.java:1453)
	at org.apache.jsp.tag.meta.http_003a.autodata_net.chrysler.us.brands.tags.layout.layout.master_tag._jspx_meth_c_005fotherwise_005f1(master_tag.java:1424)
	at org.apache.jsp.tag.meta.http_003a.autodata_net.chrysler.us.brands.tags.layout.layout.master_tag._jspx_meth_c_005fchoose_005f1(master_tag.java:1338)
	at org.apache.jsp.tag.meta.http_003a.autodata_net.chrysler.us.brands.tags.layout.layout.master_tag.doTag(master_tag.java:539)
	at org.apache.jsp.WEB_002dINF.jsp.customize_jsp._jspx_meth_layout_002dcommon_005fmaster_005f0(customize_jsp.java:100)
	at org.apache.jsp.WEB_002dINF.jsp.customize_jsp._jspService(customize_jsp.java:72)
	at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
	at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:433)
	at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:389)
	at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:333)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:304)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:684)
	at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:471)
	at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:402)
	at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:329)
	at org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:238)
	at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:262)
	at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1157)
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:927)
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:827)
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882)
	at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:778)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:304)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:224)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:185)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:151)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
	at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:929)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:405)
	at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:269)
	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:515)
	at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:300)
	at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
	at java.lang.Thread.run(Thread.java:662)
Caused by: java.io.FileNotFoundException: http://www.dodge.com/en/includes/vendor_footer.html
	at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1434)
	at org.apache.taglibs.standard.tag.common.core.ImportSupport.acquireReader(ImportSupport.java:349)
	... 46 more

[Palak Mathur]

chaitanya karthikk wrote:@Mathur: I tried with these settings

-Dhttp.proxyUser=akash.malwa.proxy
-Dhttp.proxyPassword=logmein667#
-Dhttp.proxyHost=192.168.6.241
-Dhttp.proxyPost=8080

??? What is the error that you are getting?

[chaitanya karthikk]

Palak Mathur wrote:
??? What is the error that you are getting?

Please refer the above edited post. Before I recognized and edited the post you replied. Thanks for the quick reply.

[Palak Mathur]

chaitanya karthikk wrote:

Palak Mathur wrote:
??? What is the error that you are getting?

Please refer the above edited post. Before I recognized and edited the post you replied. Thanks for the quick reply.

Did you try some other page?

[chaitanya karthikk]

Yes many pages. I referred to this link also

https://coderanch.com/t/206904/sockets/java/accessing-URL-through-java-behind

and the same errors again

[chaitanya karthikk]

I tried this method also. But all my efforts are failing. I referred this link

package com.example;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import sun.misc.BASE64Encoder;

@SuppressWarnings("serial")
public class ConnectionStream extends HttpServlet {
	public void doGet(HttpServletRequest request, HttpServletResponse response) {
		try {
		    System.getProperties().put("http.proxyHost", "192.168.6.241");
		    System.getProperties().put("http.proxyPort", "80");
		    URL url = new URL("http://www.dodge.com/en/includes/vendor_footer.html");
		    HttpURLConnection uc = (HttpURLConnection)url.openConnection();
		    System.getProperties().put("http.proxyPassword", "logmein667#");
		    System.getProperties().put("http.proxyUser", "akash.malwa.proxy");
//			Proxy proxy = new Proxy(Proxy.Type.HTTP, new InetSocketAddress("123.0.0.1", 8080));
		    String encoded = new String
		    	      ("YWthc2gubWFsd2EucHJveHk6bG9nbWVpbjY2NyM=");
		    BASE64Encoder encoder = new BASE64Encoder();
		    encoded = encoder.encode("192.168.6.241\\akash.malwa.proxy:logmein667#".getBytes());
		    	uc.setRequestProperty("Proxy-Authorization", "Basic " + encoded);
		    	uc.connect();
			InputStream is = uc.getInputStream();
			BufferedReader br = new BufferedReader(new InputStreamReader(is));
			String temp = null;
			PrintWriter out = response.getWriter();
			while((temp=br.readLine())!=null) {
				out.print(temp);
			}
		} catch(MalformedURLException e) {
			e.printStackTrace();
		} catch(IOException e) {
			e.printStackTrace();
		}
	}
}

[chaitanya karthikk]

Even when I try to open a connection to a machine on my network it is throwing FileNotFoundException.

The url I gave is

http://192.168.53.32:8080/test/sample.html

[Palak Mathur]

chaitanya karthikk wrote:Even when I try to open a connection to a machine on my network it is throwing FileNotFoundException.

The url I gave is

http://192.168.53.32:8080/test/sample.html

Are you able to ping the local machine? Also check with admin, if it is allowing you to access those web urls through the proxy.

[chaitanya karthikk]

Palak Mathur wrote:Are you able to ping the local machine? Also check with admin, if it is allowing you to access those web urls through the proxy.

I am able to ping it. Beside I tried another example from this link. All attempts are failing.

package com.example;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.Authenticator;
import java.net.MalformedURLException;
import java.net.PasswordAuthentication;
import java.net.URL;

public class TestConnection {
	public static void main(String kk[]) {
		System.getProperties().put("http.proxyHost", "192.168.6.241");
	    System.getProperties().put("http.proxyPort", "80");
	    System.getProperties().put("http.auth.preference", "HTTPS");
		MyAuthenticator authenticator = new MyAuthenticator();
		Authenticator.setDefault(authenticator);
		try {
			URL url = new URL("http://www.dodge.com/en/includes/vendor_footer.html");
			InputStream is = url.openConnection().getInputStream();
			BufferedReader br = new BufferedReader(new InputStreamReader(is));
			String temp = null;
			while((temp = br.readLine()) != null) {
				System.out.println(temp);
			}
		} catch(MalformedURLException e) {
			e.printStackTrace();
		} catch(IOException e) {
			e.printStackTrace();
		}
	}
}

class MyAuthenticator extends Authenticator {
	public MyAuthenticator() {
		getPasswordAuthentication();
	}
	public PasswordAuthentication getPasswordAuthentication () {
        return new PasswordAuthentication ("prasanna.kumar.proxy", "logmein667#".toCharArray());
    }
}

I am getting the following exception

java.io.FileNotFoundException: http://www.dodge.com/en/includes/vendor_footer.html
	at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1434)
	at com.example.TestConnection.main(TestConnection.java:21)

[chaitanya karthikk]

Thank god!!! The problem is with

System.getProperties().put("http.proxyPort", "80");

The port has to be set to 8080. Now its working. However I am not getting the entire web page. And I am not sure this is the right approach. Because I am hard coding the properties using System.getProperties().put(String,String)

Whereas I have only class files. The developers who supplied the code to me have proxy disabled, so they don't need to use the code.

I want to know is there any way to add these to the VM parameter list?

[Palak Mathur]

chaitanya karthikk wrote:Thank god!!! The problem is with

System.getProperties().put("http.proxyPort", "80");

The port has to be set to 8080. Now its working. However I am not getting the entire web page. And I am not sure this is the right approach. Because I am hard coding the properties using System.getProperties().put(String,String)

Whereas I have only class files. The developers who supplied the code to me have proxy disabled, so they don't need to use the code.

I want to know is there any way to add these to the VM parameter list?

Check the posts above, we have already suggested how to set the system property using VM parameter list. You should not require this code then.

[chaitanya karthikk]

Yes, but I have to check and make sure.

[chaitanya karthikk]

As I see there is not VM parameter to set the proxy user is and proxy password. So we have to use the Authenticator class as I see it.

[Tim Holloway]

You are using a read line but a print string. That means that no line-terminator characters are being output. Use println() instead.

In addition to the loss of fidelity, end-of-line typically triggers a buffer flush, without which you could fail to push out all of the input. Although an explicit flush after end-of-file wouldn't hurt.

[chaitanya karthikk]

Tim Holloway wrote:You are using a read line but a print string. That means that no line-terminator characters are being output. Use println() instead.

In addition to the loss of fidelity, end-of-line typically triggers a buffer flush, without which you could fail to push out all of the input. Although an explicit flush after end-of-file wouldn't hurt.

I did not understand

[Palak Mathur]

Tim Holloway wrote:You are using a read line but a print string. That means that no line-terminator characters are being output. Use println() instead.

In addition to the loss of fidelity, end-of-line typically triggers a buffer flush, without which you could fail to push out all of the input. Although an explicit flush after end-of-file wouldn't hurt.

Tim,

Which part of code are you referring to? Please quote that part.
Thank you.

Regards,
Palak Mathur

[Tim Holloway]

       while((temp=br.readLine())!=null) {  
             out.print(temp);  
      }  

[chaitanya karthikk]

Ok. Do you mean I should not use println() inside a loop while trying to read form a stream?

[Tim Holloway]

chaitanya karthikk wrote:Ok. Do you mean I should not use println() inside a loop while trying to read form a stream?

No, I mean the problem is that you didn't use a println(). You used print().

For a truly faithful (and higher-performance) copy, you would actually want to use a bulk copy, pre-allocating a fixed-sized buffer and filling it up as much as possible on each read/write iteration instead of line-by-line. But in the case of an HTTP output stream, it isn't essential to do that.

[Palak Mathur]

Tim Holloway wrote:

chaitanya karthikk wrote:Ok. Do you mean I should not use println() inside a loop while trying to read form a stream?

No, I mean the problem is that you didn't use a println(). You used print().

For a truly faithful (and higher-performance) copy, you would actually want to use a bulk copy, pre-allocating a fixed-sized buffer and filling it up as much as possible on each read/write iteration instead of line-by-line. But in the case of an HTTP output stream, it isn't essential to do that.

In his another code that he quoted in a later post, he has used println() though without knowing the advantages and disadvantages. Thank you for the explanation and above all having an eye for such details. I surely missed it.

[chaitanya karthikk]

Tim Holloway wrote:

chaitanya karthikk wrote:Ok. Do you mean I should not use println() inside a loop while trying to read form a stream?

No, I mean the problem is that you didn't use a println(). You used print().

For a truly faithful (and higher-performance) copy, you would actually want to use a bulk copy, pre-allocating a fixed-sized buffer and filling it up as much as possible on each read/write iteration instead of line-by-line. But in the case of an HTTP output stream, it isn't essential to do that.

Now I am really confused. I dont understand what you are saying. Can you please explain in little bit detail. I am sorry.