CustomValve.java

package com.freemindcafe.https.clientauth;

import java.io.IOException;
import java.security.cert.X509Certificate;

import javax.naming.InvalidNameException;
import javax.naming.ldap.LdapName;
import javax.naming.ldap.Rdn;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;

import org.apache.catalina.connector.Request;
import org.apache.catalina.connector.Response;
import org.apache.catalina.valves.ValveBase;

public class CustomValve extends ValveBase{

    @Override
    public void invoke(Request arg0, Response arg1) throws IOException,
            ServletException {
        HttpServletRequest req = arg0;
        X509Certificate certs[] = 
                (X509Certificate[])req.getAttribute("javax.servlet.request.X509Certificate");
        String dn = certs[0].getSubjectX500Principal().getName();
        LdapName ldapDN;
        try {
            ldapDN = new LdapName(dn);
            for(Rdn rdn: ldapDN.getRdns()) {
                System.err.println(rdn.getType() + " -> " + rdn.getValue());
            }
        } catch (InvalidNameException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

}